US Open, 7 September 2026: Fresh Legs Challenge Major Pedigree

The US Open men’s fourth round continues on 7 September with an unusually open section of the draw. Alexander Zverev carries the highest expectation, while Francisco Cerundolo, Karen Khachanov and Botic Van De Zandschulp must manage opponents playing without much fear.

Fitness matters as much as reputation across these four matches. Several players have already spent heavily in five-set contests, and the cleanest serve routines and second-serve holds may decide who still has legs in the pressure games. These are the matches I find most compelling:

17:00 — Francisco Cerundolo — Alexander Blockx
20:00 — Karen Khachanov — Learner Tien
20:30 — Arthur Gea — Botic Van De Zandschulp
00:30 — Alexander Zverev — Luciano Darderi

Times are UTC; Zverev–Darderi begins on 8 September.

Francisco Cerundolo — Alexander Blockx

Cerundolo has produced the more dramatic tournament, but Blockx has played the cleaner tennis. The Argentine needed five sets against Jan-Lennard Struff and then recovered from two sets down to beat Taylor Fritz 3-6, 4-6, 6-3, 6-4, 6-4. He escaped a dangerous late service game in the decider before immediately putting the pressure back on Fritz, which was the best example of his discipline all night.

Cerundolo admitted, “I wasn’t feeling comfortable at all” (US Open). His forehand eventually found its weight and shape, but two consecutive five-set recoveries leave a real physical bill. The legs do not issue medals for bravery.

Blockx followed two controlled wins by beating sixth-ranked Flavio Cobolli 6-7(4), 6-3, 6-0, 6-3. He did not retreat when Cobolli briefly recovered momentum. He returned to compact first-strike patterns, hit firmly through the middle and made the final service games uncomplicated.

The Belgian also owns their only previous meeting, a 7-6(8), 6-2 win on Madrid clay in April. Hard court gives his serve and flatter acceleration even more value, although Cerundolo has the wider range of spins and heights. Cerundolo must move Blockx laterally and protect his own backhand corner; short second serves will allow Blockx to take control before the rally develops.

I think Blockx is closer to the win because his patterns are sharper and his recovery position is much better. The −2.5-game handicap looks achievable if he keeps his return games direct and avoids turning the match into another Cerundolo survival exercise.

Karen Khachanov — Learner Tien

Khachanov has restored order after a poor North American build-up. He dropped the opening set against Felix Auger-Aliassime but kept making the Canadian play physical points as illness and dizziness intervened, then dismissed Benjamin Bonzi 6-3, 6-2, 6-4. The important detail was not the score but the absence of loose service games.

Tien’s route has been more emotional. He handled Nuno Borges and Gael Monfils in straight sets before beating Jakub Mensik 6-3, 1-6, 6-7(2), 6-3, 6-4 in a late-night fight. Tien immediately answered an early break in the fourth set and kept extending rallies until Mensik’s first strike became less reliable. “I think the crowd played a huge role in the match,” he said afterward (US Open).

They have not met before. Khachanov has the larger serve and the simpler route to short points, while the left-handed Tien changes direction early and turns defence into attack without becoming passive. Khachanov will want the contest to resemble a disciplined cross-court drill: heavy first serve, firm first forehand and no unnecessary change of direction until the opening is clear.

Tien’s return position and ability to bring Khachanov forward can disturb that order. His concern is recovery after the Mensik match and the emotional drop following a charged home-crowd finish. Khachanov is fresher, but he cannot afford hesitant second serves or passive backhand exchanges.

I lean narrowly toward Khachanov despite Tien being the market favourite. Khachanov’s +3.5-game line offers protection in a match that could reach four or five sets, and the 39.5 total looks reachable if Tien’s legs hold through the middle stages.

Arthur Gea — Botic Van De Zandschulp

Gea entered the draw as a lucky loser and has since survived two five-set matches. He recovered from two sets to one down against Juan Manuel Cerundolo, then did the same against Michael Zheng in a contest lasting close to four hours. His hard-court results this season are excellent, but the loose passages against Zheng showed how quickly his shot selection can unravel.

“Of course, I’m a bit tired,” Gea conceded (US Open). Van De Zandschulp has no recovery advantage after his own five-set escape against Zizou Bergs, although he has already produced the best single performance of this matchup by beating seventh-ranked Alex De Minaur 6-4, 7-5, 6-2.

There is no previous meeting. Van De Zandschulp owns the heavier, flatter ball and the more stable hard-court structure. Gea must crowd his preparation, move him repeatedly and attack the second shot before the Dutchman establishes his preferred hitting position.

I expect Van De Zandschulp’s weight of shot to decide the match, provided his legs recover from the Bergs contest. He is the likelier winner, and −2.5 games looks reasonable, though Gea’s freedom makes a routine afternoon unlikely.

Alexander Zverev — Luciano Darderi

Zverev finally produced a controlled performance against Alejandro Tabilo, winning 6-2, 7-6(2), 6-2 after five-set struggles with Lorenzo Sonego and Quentin Halys. His serve gave him predictable first balls, his backhand closed the cross-court lane and his baseline position was firmer. That was the first match in which he looked like the leading contender in this part of the draw rather than a player negotiating an emergency.

Darderi also arrives after a useful straight-sets win, beating Dane Sweeny 6-4, 6-3, 6-3. He defended more willingly and waited for the right forehand instead of forcing every neutral ball. His hard-court record has improved to nine wins from 17 matches this season, but Zverev presents a much harsher test of his second serve and backhand stability.

The head-to-head is tied at one win each, both meetings coming on Rome clay. Zverev won 7-6(3), 6-2 in 2024, while Darderi overturned a one-sided opening set to win 1-6, 7-6(10), 6-0 in May after escaping multiple match points. That result gives Darderi genuine belief, but the hard court strengthens Zverev’s serve and allows his backhand to absorb the Italian’s heavy forehand more comfortably.

Before the tournament, Zverev said, “I’m one of the 128 players that are favourites in the draw” (ATP). The draw has now removed that camouflage. Zverev must hold the baseline, attack Darderi’s second serve and avoid the passive court position that prolonged his first two matches.

I expect Zverev to win in straight sets if his forehand remains committed. The −7.5-game handicap demands near-total control, so under 33.5 games is the cleaner reflection of a match Zverev should keep short.

Freshness, second serves and the weight of expectation

The central question is whether the younger breakthroughs can preserve their aggression once the fourth-round pressure games arrive. Blockx has the clearest physical advantage, Tien has the most disruptive tactical game, and Gea still carries the freedom of a player who had already expected to leave New York.

I see Zverev as the strongest favourite, with Khachanov–Tien the day’s most delicate tactical argument. The AI cappers’ concrete selections are available on the individual match pages, where the margins, totals and match-specific risks are set out in full.