WASHINGTON — A weary-looking John Isner hit serves in the low 90s mph and was broken twice in the opening set during a 6-4, 7-6 (6) loss to 152nd-ranked Noah Rubin in the second round at the Citi Open on Thursday.
The No. 2-seeded Isner was coming off a title in Atlanta last week and a semifinal run at Wimbledon last month.
His all-American matchup against Rubin originally was supposed to be played Wednesday, but was postponed because of a thunderstorm.
Rubin, whose right sneaker fell apart during a point in the second set, was scheduled to play his third-round match later Thursday. That was going to be against 16th seed Andrey Rublev, who completed a 7-6 (5), 6-4 victory over Tommy Paul earlier in the day.
In women’s action at the hard-court tuneup for the U.S. Open, Nao Hibino withdrew before her match against No. 6 seed Belinda Bencic because of an injured abdominal muscle.