NEW YORK: Alexander Blockx arrived at the 2026 US Open having never played a main-draw match at Flushing Meadows.
He is now a quarterfinalist.
The 21-year-old Belgian defeated No. 24 seed Francisco Cerúndolo 6-3, 4-6, 7-5, 7-5 in the Round of 16 at Arthur Ashe Stadium, becoming the first Belgian man to reach the US Open quarterfinals.
That achievement would already make this one of the defining stories of the men’s tournament.
The route makes it more significant.
Blockx had already eliminated No. 5 seed Flavio Cobolli in the third round, overturning a recent Cincinnati defeat and securing the biggest win of his young career.
Cerúndolo presented another completely different problem.
The Argentine entered Monday carrying enormous confidence after recovering from two sets down to eliminate 2024 US Open finalist Taylor Fritz.
Blockx stopped that momentum.
He took the first set, responded after losing the second and then won two tight 7-5 sets to close the match without allowing Cerúndolo to drag him into a fifth.
The victory sends Blockx into his first Grand Slam quarterfinal.
It also transforms what had already been an excellent breakthrough tournament into a piece of Belgian tennis history.
Alexander Blockx vs Francisco Cerúndolo: Match at a Glance
| Detail | Information |
|---|---|
| Round | US Open 2026 Round of 16 |
| Winner | Alexander Blockx |
| Loser | Francisco Cerúndolo |
| Score | 6-3, 4-6, 7-5, 7-5 |
| Blockx seed | No. 28 |
| Cerúndolo seed | No. 24 |
| Venue | Arthur Ashe Stadium |
| Major significance | Blockx becomes first Belgian man to reach US Open quarterfinals |
| Next opponent | Karen Khachanov |
The official US Open men’s singles draw confirms Blockx’s progression into the last eight and his quarterfinal place opposite Karen Khachanov.
Blockx Has Gone From Promising Prospect to Grand Slam Quarterfinalist in One Week
Every major breakthrough eventually reaches the point where the language around a player has to change.
Blockx is reaching that point in New York.
Before this tournament, he was one of the more interesting young players beneath the established ATP elite.
He had already shown enough power, athleticism and confidence to make experienced opponents uncomfortable.
That is different from proving those qualities across four rounds of a Grand Slam.
The US Open has removed much of the uncertainty.
Blockx is no longer merely playing well enough to trouble established players.
He is beating them.
And he is doing it repeatedly.
The Cobolli Win Was the First Sign This Run Could Become Much Bigger
The first major warning arrived in the third round.
Flavio Cobolli entered the US Open as the No. 5 seed and one of the most dangerous players outside the traditional championship favorites.
The Sports Encounter had already followed Cobolli’s tournament closely, including his spectacular tweener and difficult opening rounds in our feature on Cobolli, Alexandra Eala and Taylor Fritz.
Cobolli had also beaten Blockx only weeks earlier in Cincinnati.
New York reversed that result.
Blockx defeated him 3-6, 6-3, 6-0, 6-3.
The official US Open report on Blockx’s upset of Cobolli noted that the Belgian struck 17 aces and 41 winners while producing the first Top 10 victory of his Grand Slam career.
That match moved Blockx from interesting outsider to genuine second-week threat.
Cerúndolo has now discovered the same thing.
Cerúndolo Arrived With One of the Best Wins of the Tournament
Blockx did not receive a favorable fourth-round opponent simply because Cobolli had disappeared.
Cerúndolo had just eliminated Taylor Fritz in one of the most dramatic matches of the men’s first week.
Fritz won the opening two sets.
Cerúndolo responded by winning the next three.
The American had entered the tournament in outstanding early-round form, having lost only two games against Mattia Bellucci in Round 2.
The Sports Encounter’s coverage of Fritz’s dominant start showed why he looked like one of the strongest home hopes before Cerúndolo changed the entire section of the draw.
Our subsequent US Open quarterfinal-race analysis identified Fritz’s exit as another sign that the men’s tournament had become far more open than the seedings suggested.
Cerúndolo had earned the right to believe he could take advantage.
Blockx ended that possibility.
The First Set Showed Blockx Was Not Intimidated by Arthur Ashe Stadium
Arthur Ashe Stadium changes matches before the first ball is struck.
Players who look relaxed on outside courts can become more conservative when the scale of the arena becomes unavoidable.
Blockx did not play like a 21-year-old seeing that stage as an obstacle.
He took the opening set 6-3.
That early scoreboard control mattered because Cerúndolo had spent so much of his previous match proving how dangerous he becomes when allowed time to adjust.
Blockx forced him into another recovery immediately.
Cerúndolo’s Second-Set Response Created the Real Test
The Argentine took the second set 6-4.
At that point, the match could easily have moved toward Cerúndolo’s preferred pattern.
He had already survived multiple long matches.
He had just overturned Fritz from two sets down.
He had experience managing physical uncertainty deep into best-of-five contests.
Blockx needed to stop the match becoming another Cerúndolo endurance story.
He did.
Winning the Third Set 7-5 Was the Most Important Passage
The third set carried enormous weight.
At one set apiece, the winner would move within one set of the quarterfinal.
Blockx took it 7-5.
That result forced Cerúndolo to chase again.
It also showed that the Belgian could win a tight set rather than depend only on dominant serving runs or sudden momentum swings.
Grand Slam second weeks increasingly become about exactly these situations.
Everyone can strike winners.
Everyone can serve.
Everyone has survived enough matches to believe.
The separation comes from who executes when the scoreboard becomes uncomfortable.
Another 7-5 Set Closed the Door Before a Fifth Could Begin
The fourth set followed a similar pattern.
Cerúndolo remained close enough to keep the threat of a deciding set alive.
Blockx refused to give him one.
Another 7-5 finish completed the victory.
That detail is significant.
A fifth set would have brought Cerúndolo’s previous survival experience back into the match.
It would also have added another physical layer to Blockx’s workload before the quarterfinal.
Closing in four preserved both momentum and energy.
Blockx Has Already Beaten Two Players Who Entered With Far More Major Experience
| Opponent | Round | Result | Why It Mattered |
|---|---|---|---|
| Flavio Cobolli | Round 3 | Blockx won 3-6, 6-3, 6-0, 6-3 | Defeated No. 5 seed and French Open finalist |
| Francisco Cerúndolo | Round of 16 | Blockx won 6-3, 4-6, 7-5, 7-5 | Stopped Fritz conqueror and reached first major quarterfinal |
The sequence matters because the two opponents required different solutions.
Cobolli brought more immediate firepower.
Cerúndolo brought greater clay-court-style patience, point construction and recent five-set confidence.
Blockx found a way through both.
Belgian Men’s Tennis Has Its First US Open Quarterfinalist
This is the historical part of the result.
Blockx is the first Belgian man to reach the US Open quarterfinals.
Belgium has produced accomplished men’s players before him.
David Goffin reached multiple Grand Slam quarterfinals and climbed into the world’s Top 10.
Xavier Malisse reached a Wimbledon semifinal.
Olivier Rochus built a long and respected career on the ATP Tour.
None reached the men’s singles quarterfinals in New York.
Blockx has.
At 21.
On his US Open main-draw debut.
Why This Run Matters for Belgian Tennis Beyond One Tournament
National tennis programs need visible proof that development pathways can produce players capable of competing at the highest level.
One Grand Slam quarterfinal does not guarantee a decade of Belgian success.
It can change expectations around the players coming behind him.
Young athletes see a route.
Federations gain a stronger commercial and competitive reference point.
Domestic audiences become more engaged with a player who has moved from promising to globally relevant within days.
Blockx’s breakthrough therefore carries value beyond his own ranking.
His Age Makes the Achievement Even More Interesting
Blockx is 21.
That places him inside the generation increasingly challenging the established hierarchy rather than waiting for it to disappear.
The men’s US Open has reinforced that trend repeatedly.
Alex Michelsen reached his first Grand Slam quarterfinal.
Learner Tien reached the Round of 16.
Ben Shelton remains a major American contender.
Arthur Gea has produced one of the tournament’s most unexpected runs.
The Sports Encounter’s analysis of the reshaped quarterfinal race argued that opportunity only matters when emerging players convert it.
Blockx has converted it more dramatically than almost anyone.
The Men’s Draw Has Been Losing Established Names Since the Opening Round
The context makes this breakthrough even more important.
Novak Djokovic lost in Round 1.
Arthur Fils disappeared early.
Andrey Rublev went out.
Felix Auger-Aliassime was eliminated.
Fritz lost.
Cobolli lost.
The Sports Encounter’s early tournament analysis documented how quickly the original hierarchy began collapsing.
That created opportunity across several sections of the bracket.
Blockx has now taken advantage better than most.
His New York Run Did Not Begin With Major Expectations
There is a temptation once a player reaches the quarterfinals to rewrite the opening week as if the breakthrough had always looked inevitable.
It did not.
Blockx entered New York seeded No. 28.
That made him dangerous.
It did not make him an obvious quarterfinal pick.
The original title discussion centered on players such as Carlos Alcaraz, Alexander Zverev, Djokovic, Fritz, Shelton, Daniil Medvedev and others with deeper major résumés.
The Sports Encounter’s early men’s tournament wrap reflected that hierarchy while also noting the growing depth underneath the established contenders.
Blockx is now one of the strongest examples of that depth becoming reality.
Cincinnati Provided a Warning Before New York
Blockx’s rise did not begin at the US Open.
His North American hard-court season had already produced evidence that he could compete with players above him.
Cobolli beat him in Cincinnati, but the match was close enough to provide information rather than discouragement.
New York gave Blockx another chance against the Italian.
He used it.
The wider Cincinnati tournament had already suggested that the gap between the leading men’s players and the chasing group was becoming less comfortable.
The Sports Encounter’s analysis of Arthur Fils’ Cincinnati title and the changing US Open race argued that several players outside the traditional favorites were arriving in New York with legitimate reasons to believe.
Blockx has now taken that idea further.
His First Grand Slam Season Is Already Producing a Major Quarterfinal
According to the US Open, Blockx is playing his first full season of Grand Slam main-draw tennis.
That makes the learning curve unusually steep.
Best-of-five tennis asks different questions from regular tour events.
Physical recovery matters more.
Momentum lasts longer.
Poor sets do not necessarily end matches.
Concentration must survive three, four or five hours rather than one strong 90-minute stretch.
Blockx has adapted rapidly.
The Cobolli Match Showed His Power, Cerúndolo Showed His Composure
The two biggest victories of his run reveal complementary qualities.
Against Cobolli, the numbers were spectacular.
Seventeen aces.
Forty-one winners.
A 6-0 third set.
That was a statement of raw ability.
Cerúndolo required something different.
There was no 6-0 runaway set.
There were two 7-5 sets instead.
That is a statement of competitive maturity.
What Does Blockx Need to Do Against Karen Khachanov?
The quarterfinal changes the problem again.
Karen Khachanov brings far more Grand Slam experience than anyone Blockx has faced so far.
The Russian reached the US Open semifinals in 2022 and has built a career around powerful serving, heavy groundstrokes and an ability to remain physically stable deep into best-of-five matches.
Blockx cannot assume the same level of scoreboard volatility will appear.
Khachanov has seen these stages before.
That makes early pressure particularly valuable.
Blockx Cannot Allow Khachanov to Settle Into Service Rhythm
Khachanov becomes difficult to break when his first serve begins controlling points.
Blockx therefore needs to make return games physically and mentally uncomfortable even when immediate breaks do not arrive.
That means forcing second serves.
Getting neutral returns deep enough to begin rallies.
Making Khachanov play additional balls rather than allowing easy service holds.
His Own First Serve Must Remain a Weapon
Blockx’s serve has carried him through difficult stretches throughout this run.
Against Cobolli, 17 aces created repeated opportunities to escape pressure.
Khachanov is a stronger returner than several earlier opponents and is less likely to donate entire games through impatience.
Blockx therefore needs a high first-serve percentage without becoming predictable.
The Physical Question Becomes Bigger With Every Round
Four Grand Slam matches already create a substantial workload.
Blockx has now played enough high-intensity tennis for recovery to become part of the quarterfinal story.
The good news is that he avoided a fifth set against Cerúndolo.
The broader tournament has repeatedly shown how different scheduling and match length can shape later rounds.
The Sports Encounter’s analysis of the rain-disrupted opening week identified recovery time as one of the hidden variables created by New York’s uneven schedule.
By the quarterfinals, those accumulated differences begin to matter more.
Blockx Is Also Benefiting From the Draw Opening Around Him
This does not diminish what he has achieved.
It explains the opportunity.
Fritz was supposed to be one of the most difficult players in this section.
Cerúndolo removed him.
Cobolli was the No. 5 seed.
Blockx removed him.
Now the Belgian is in the final eight without having to face the original highest-ranked names expected to dominate his section.
That is how Grand Slam draws evolve.
Players cannot control who disappears.
They can control whether they exploit the opening.
Blockx has.
The Pressure Changes Once a Breakthrough Becomes National History
The first week allowed Blockx to play with relatively limited external expectation.
That luxury is disappearing.
Belgian attention will increase sharply before the quarterfinal.
International media coverage will grow.
The storyline will change from surprise to possibility.
Can he reach the semifinals?
Can he challenge for the title?
Can he become Belgium’s next consistent Top 20 player?
Those questions are natural.
They can also become distracting.
His best response is to continue treating the tournament as a sequence of matches rather than a national event.
New York Has Been Rewarding Players Who Ignore Reputation
Blockx’s run fits the wider personality of this US Open.
Zheng Qinwen has reached the women’s quarterfinals from qualifying.
Alex Michelsen has made his first major quarterfinal.
Arthur Gea has moved far beyond expectations.
Several major seeds are already gone.
The Sports Encounter’s second-week tournament analysis described a draw increasingly defined by players converting unexpected openings.
Blockx has become one of its central examples.
What Would a Semifinal Mean for Blockx?
A victory over Khachanov would push the achievement into another category.
A quarterfinal can sometimes emerge from a favorable section, one major upset and strong momentum.
A semifinal requires surviving five Grand Slam matches and defeating another last-eight opponent who knows exactly what the stage demands.
That would establish Blockx as more than a one-tournament breakthrough.
It would make him an immediate factor in future major seeding and hard-court expectations.
What Would This Run Mean for His Ranking?
Grand Slam quarterfinals deliver major ranking points.
For a young player still building his position inside the ATP hierarchy, that can significantly change tournament access and seeding opportunities over the following months.
Higher rankings reduce the likelihood of drawing elite seeds in the opening rounds.
That creates more opportunities to build consistent second-week appearances rather than needing major upsets immediately.
The official ATP profile for Alexander Blockx tracks his current ranking, tournament results and progression across the 2026 season.
The Bigger Question Is Whether This Level Can Travel Beyond New York
Every Grand Slam creates temporary stars.
The difficult part comes afterward.
Opponents study more film.
Expectations rise.
First-round matches become less anonymous.
Players begin preparing specifically for the strengths that initially surprised them.
Blockx’s long-term development will therefore depend on whether the serve, forehand aggression and competitive composure remain effective once opponents begin treating him like an established threat.
TSE Analysis: How Far Can Alexander Blockx Actually Go?
Far enough that a semifinal is no longer an unrealistic question.
That does not mean Khachanov should suddenly be treated as the underdog.
Experience still matters.
Khachanov has played deep into majors before.
He understands how quarterfinal pressure changes service games and tiebreaks.
Blockx is experiencing almost everything for the first time.
But the Belgian has already answered two important questions.
Can he beat a player ranked far above him at a Grand Slam?
Cobolli answered that.
Can he then return two days later and beat another dangerous opponent after the emotional high of the first upset?
Cerúndolo answered that.
That second question is often the more important one.
One major upset can happen because an established player has a poor day.
Two significant wins in succession begin to describe the player producing them.
Blockx has shown power.
He has shown recovery.
He has shown composure in tight sets.
He has shown that Arthur Ashe Stadium does not frighten him.
The next examination is whether those qualities survive when history is no longer the surprise waiting at the end of the match.
It is now the expectation surrounding the beginning.
Belgium already has its first men’s US Open quarterfinalist.
Blockx now gets to decide whether that historic sentence needs another line.
Frequently Asked Questions
Who won Alexander Blockx vs Francisco Cerúndolo at the US Open 2026?
Alexander Blockx defeated Francisco Cerúndolo 6-3, 4-6, 7-5, 7-5 in the Round of 16.
Has Alexander Blockx reached a Grand Slam quarterfinal before?
No. The 2026 US Open is the first Grand Slam quarterfinal of Blockx’s career.
Is Alexander Blockx the first Belgian man to reach the US Open quarterfinals?
Yes. Blockx became the first Belgian man to reach the men’s singles quarterfinals at the US Open.
How old is Alexander Blockx?
Blockx is 21 years old during the 2026 US Open.
Who did Blockx beat before Cerúndolo?
Blockx defeated No. 5 seed Flavio Cobolli 3-6, 6-3, 6-0, 6-3 in the third round.
Who did Francisco Cerúndolo beat before facing Blockx?
Cerúndolo defeated Taylor Fritz in five sets after recovering from two sets down.
Who will Alexander Blockx play next?
Blockx will face Karen Khachanov in the US Open quarterfinals.
Has Karen Khachanov reached a US Open semifinal before?
Yes. Khachanov reached the US Open semifinals in 2022.
Did Blockx play Cobolli before the US Open?
Yes. Cobolli defeated Blockx in Cincinnati earlier in the 2026 North American hard-court season before Blockx reversed the result in New York.
What seed is Alexander Blockx at the US Open?
Blockx is the No. 28 seed in the men’s singles draw.