Khachanov Outlasts Tien in Five Sets to Reach US Open Quarterfinals

What happened

Watch the highlights:

Karen Khachanov outlasted 14th-seeded Learner Tien in a five-set US Open fourth-round contest, winning 7-5, 4-6, 6-7(6), 6-1, 6-4 at Louis Armstrong Stadium. Tennis.com's completed match page recorded the contest and showed how sharply the momentum changed after Tien edged the third-set tiebreak. Khachanov answered by conceding only one game in the fourth set, then found the decisive break in the fifth to close out the match.

The match statistics explain why Khachanov survived a contest that lasted nearly four hours. Tennis.com credited him with winning 81 of 110 first-serve points, compared with 68 of 100 for Tien. Khachanov also converted nine of 12 break-point opportunities while Tien converted five of 14. That efficiency helped offset a competitive match in which both players had spells of control and Tien came within one set of extending his best US Open run.

Why it matters

Khachanov arrived in New York unseeded and with a 16-18 record for the season, according to the official US Open website, but his Grand Slam record made him a dangerous draw. The same official profile noted that he has reached the quarterfinals at all four majors and previously advanced to the semifinals in both New York and Melbourne. This victory returns him to the US Open's last eight and reinforces his reputation as a player whose power and physical durability become more valuable in best-of-five-set matches.

The result also ends a notable run for Tien. The American had reached the fourth round by beating Jakub Mensik in five sets, 6-3, 1-6, 6-7(2), 6-3, 6-4, according to USOpen.org. Against Khachanov, Tien again pushed a more experienced opponent deep into a deciding set. His ability to take the third-set tiebreak and keep retrieving under pressure showed why he has become one of the leading young players on the men's tour, even though Khachanov's first-strike tennis ultimately proved more reliable.

Tournament impact

Khachanov will face 21-year-old Belgian Alexander Blockx in the quarterfinals. The official tournament site reports that Blockx reached the last eight in his first US Open main draw by defeating Francisco Cerundolo 6-3, 4-6, 7-5, 7-5. Blockx had already eliminated sixth-seeded Flavio Cobolli, so Khachanov's experience will be tested against one of the event's breakout players rather than an established favorite.

What to watch

The quarterfinal is likely to turn on whether Khachanov can reproduce the serving and break-point efficiency he showed against Tien. Blockx has already demonstrated that he can absorb pressure and finish tight sets, while Khachanov has now come through a demanding five-set match. Recovery, first-serve percentage and early control of return games will be the central indicators when they meet for a semifinal place.