Learner Tien Wins Five-Set US Open Fight Against Jakub Mensik

What happened

Watch the highlights:

Learner Tien reached the fourth round of the US Open for the first time by defeating Jakub Mensik 6-3, 1-6, 6-7(2), 6-3, 6-4 in Louis Armstrong Stadium. The official US Open report says the third-round match lasted three hours and 24 minutes, with the American recovering after Mensik took two of the middle three sets.

Tien began strongly but had to reset after losing the second set and then the third-set tiebreak. He levelled the match by taking the fourth set 6-3 before securing the deciding set 6-4. The result extended his best run at his home Grand Slam and sent a home player into the second week after a match shaped by contrasting styles.

The US Open described Mensik as the more powerful server and ball-striker, while Tien relied on patience, variety and his ability to absorb pressure. Crowd support in Armstrong Stadium also favoured Tien, who had played Gael Monfils on the same court in the previous round. This time, the New York audience was firmly behind the Southern Californian as he completed the comeback.

Why it matters

The victory puts Tien one win away from matching his best result at a major. He reached his first Grand Slam quarterfinal at the Australian Open earlier in 2026, and his New York performance confirms that run was not an isolated breakthrough. Winning a long fifth set after falling behind also adds evidence that he can manage the physical and tactical demands of best-of-five tennis.

Mensik leaves the singles draw, but his tournament has already included a major title. According to the official event report, he won the US Open mixed doubles championship with fellow Czech Karolina Muchova. His singles defeat therefore ends one part of a productive trip while Tien advances into an increasingly demanding section of the men's draw.

Tournament impact

Tien will next face Karen Khachanov for a place in the quarterfinals. The unseeded Khachanov has lost only one set across his opening three matches, with that dropped set coming during his second-round upset of third seed Felix Auger-Aliassime. Khachanov has previously reached the US Open semifinals, doing so in 2022, and also made the Australian Open semifinals in 2023.

That matchup presents Tien with another big server immediately after the physical challenge posed by Mensik. Tien's returning, point construction and recovery will all be tested, particularly after spending more than three hours on court in round three. Khachanov's experience deep in major tournaments gives the next match a different pressure from Tien's latest victory.

What to watch

The central question is whether Tien can neutralize Khachanov's first strike often enough to create extended rallies. His composure in the fifth set against Mensik was decisive, but recovery time and serving efficiency will matter as the tournament moves into its second week. A win would equal Tien's career-best Grand Slam result and deliver his first US Open quarterfinal.

Source note

Match score, duration, round context and next-opponent details were reported by the official US Open website on 6 September 2026: https://www.usopen.org/amp/en_US/news/articles/2026-09-06/learner_tien_wins_five-set_fight_vs_mensik_in_2026_us_open_third_round.html