No. 3 Felix Auger-Aliassime became the highest-seeded player eliminated thus far at the US Open when he lost in four sets to Karen Khachanov on Thursday.
Khachanov defeated Auger-Aliassime 6-7 (5), 6-3, 6-2, 6-2.
The highest seed to fall so far had been No. 4 Novak Djokovic, who lost in the first round at the US Open for the first time in the 24-time Grand Slam champion's career.
No. 1 Alexander Zverev hopes for an easier time against Quentin Halys later Thursday after he needed five sets to edge Lorenzo Sonego on Tuesday, barely avoiding becoming the first No. 1 seed to lose in the first round of a men's major since 2003.
Other men in action include No. 9 Taylor Fritz and Gael Monfils, who is planning to retire after this year but won Tuesday on his 40th birthday to prolong his Grand Slam career and advance to face No. 14 Learner Tien.
Information from The Associated Press was used in this report.
