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.
NEW YORK (AP) Defending champions Naomi Osaka and Novak Djokovic are the No. 1 seeds for singles play in the U.S. Open.
Osaka, who beat Serena Williams in last year’s final for her first Grand Slam title, recently regained the top spot in the WTA rankings from Ash Barty. Barty is the No. 2 seed, followed by Karolina Pliskova, Wimbledon champion Simona Halep and Elina Svitolina.
Williams was given the No. 8 seed Wednesday by the U.S. Tennis Association. Madison Keys, the 2017 runner-up who just won the Western & Southern Open, rounds out the top 10 seeds.
Djokovic, bidding for his second straight major title, is followed by fellow past U.S. Open champions Rafael Nadal and Roger Federer. Dominic Thiem is No. 4 and surging Daniil Medvedev, who won the title outside Cincinnati last week in what was his third straight tournament reaching the final, is fifth.
The draw will be held Thursday and main-draw play begins Monday.
More AP tennis: http://apnews.com/apf-Tennis and https://twitter.com/AP-Sports
NEW YORK (AP) Wimbledon semifinalist Barbora Strycova was knocked out of the Bronx Open on Tuesday with a 3-6, 6-2, 6-1 loss to Bernarda Pera.
Strycova was the No. 3 seed and was playing her opening match in the new WTA tournament after receiving a first-round bye. But the 33-year-old Czech, the oldest player in the field, was handled easily by the American wild-card entrant over the final two sets on a hot afternoon after winning the first set.
Pera will play No. 5 Katerina Siniakova, who had rolled to a 6-0, 3-0 lead over Anastasia Potapova before the Russian qualifier retired.
The other quarterfinal matchup set up Tuesday will feature Camila Giorgi, who outlasted Andrea Petkovic 3-6, 7-5, 7-6 (3), against Alize Cornet, who was leading 7-6 (5), 4-0 when Zhu Lin had to retire with an injury.