US Open: No. 5 Flavio Cobolli falls to No. 28 Alexander Blockx, No. 9 Taylor Fritz upset by No. 24 Francisco Cerúndolo in third round

In a disappointing day for higher seeds at the US Open on Saturday, No. 5 Flavio Cobolli lost decisively to No, 28 Alexander Blockx in four sets, 6-7, 6-3, 6-0, 6-3. And No. 9 Taylor Fritz lost the final three sets of his match with No. 24 Francisco Cerúndolo in a 3-6, 4-6, 6-3, 6-4, 6-4 defeat.

Blockx and Cerúndolo will now face each other in the Round of 16 on Monday.

Earlier in the day, No. 10 women's seed Amanda Anisimova and No. 22 Madison Keys suffered third-round upset defeats .

Flavio Cobolli could not recover after first-set tiebreaker

Cobolli took an early lead over Blockx in the first set, going ahead 4-2. But the Belgian came back to force a tiebreak and that effort may have worn Cobolli out — or at the very least, shook his confidence, and he could never quite recover.

Taking the first set to a tiebreaker after falling behind appeared to lift Blockx's confidence, while Cobolli looked baffled that the match slipped out of his control so definitively.

For Cobolli, the result was stunning in light of him apparently taking a significant step in his progression after advancing to the French Open final, where he lost to Alexander Zverev in a grueling five-set battle. That performance vaulted the Italian star into the top 10 of the world rankings.

Yet he got off to slow starts in his previous two matches at the US Open. In his first-round match versus Francisco Comesaña, Cobolli lost the first two sets before rallying for a five-set victory. And in the second round, he went down in the first set to Tristan Schoolkate. The mental and physical hurdles presented by overcoming those early deficits may have caught up with him in the third round.

The defeat is the second consecutive upset loss in a Grand Slam tournament this season for Cobolli. At Wimbledon as the No. 9 seed, he lost to wild card (and British home crowd favorite) Arthur Fery in three sets

Blockx advances to the Round of 16 for the first time in a Grand Slam tournament. Cobolli fails to get past the third round for the second consecutive US Open after needing to retire against Lorenzo Musetti last year.

Taylor Fritz suffered surprising collapse after early lead

Fritz appeared to be on his way to a straight-set victory after winning the first two sets rather comfortably. He wasn't completely sharp in taking that early lead, but didn't need to be as Cerúndolo committed a handful of unforced errors on his end. Additionally, he showed little defense on Fritz's returns.

However, Cerúndolo didn't let Fritz pull away, forcing him to work hard to avoid breaks on several points. One sequence in that first set was particularly compelling, resulting in a 20-shot rally. But after Cerúndolo finally broke Fritz, the American countered to break back and won that first set.

In the second set, Fritz took control early with his serve and hit several forehands that Cerúndolo couldn't reach or return. Additionally, Cerúndolo struggled with his serve, which allowed Fritz to seize control and take a two-set lead.

Early on in the third set, Fritz had the momentum while Cerúndolo became frustrated and looked like he was going to suffer a straight-set defeat. But Cerúndolo broke Fritz to tie the game at 1-1, allowing him to find his footing and settle himself.

From there, Fritz began to fall apart, suddenly committing unforced errors that he avoided while winning the first two sets. After losing the third set, Fritz was still in position to win the match. However, his composure appeared to crumble as he continued making unforced errors. At one point, he showed frustration and looked to his coaches' box for answers that weren't coming.

By the fourth set, the match made a surprising 180-degree turn. Cerúndolo gained confidence with each game and took control, while Fritz looked overmatched and consistently lost his serve.

Since reaching the US Open final in 2024, where he lost to Jannik Sinner , Fritz lost to Novak Djokovic in the quarterfinals of last year's tournament and couldn't advance past the third round this year.

It's been a good year for the Cerúndolo brothers in Grand Slam tournaments. At the French Open earlier this year, Francisco's younger brother Juan Manuel upset Sinner, ranked as the World No. 1 , in the second round.