WASHINGTON (AP) Former No. 1 Caroline Wozniacki retired from her second-round match at the Citi Open against Sam Stosur because of an injured left arm.
The right-handed Wozniacki said that she felt pain while hitting a two-handed backhand at 5-all in the first set of a match that began Wednesday night and ended just past midnight on Thursday. She was treated by a trainer and wound up winning that set 7-5, but stopped playing after getting broken to trail 4-3 in the second.
''There was a point where I hit a backhand and I just felt it, and I was like `Oh, it's nothing,''' Wozniacki said. ''But then I hit another backhand and I was like, `OK, it's something.' And it just got worse.''
It's the latest in a series of setbacks this season for Wozniacki, the U.S. Open runner-up in 2009 and 2014.
She hasn't won a Grand Slam match this year, losing in the first round at the Australian Open and Wimbledon and missing the French Open because of an injured ankle.
''At this point, I just can't catch a break. I'm thinking, `I'm going to catch a break sooner or later.' But right now, it's just like one thing after the other,'' Wozniacki said. ''I feel like I'm hitting it pretty well. I'm serving well. And it's like, this happens. It's just like really disappointing.''
Wozniacki is supposed to represent Denmark at the Rio de Janeiro Olympics next month and carry her country's flag in the opening ceremony. She won an appeal to the International Tennis Federation to allow her to compete at the Rio Games after she was unable to fulfill the Fed Cup requirements.
Against 2011 U.S. Open champion Stosur, Wozniacki was trailing 5-3 at the outset before taking four games in a row. That success came despite how hard it was for her to use her left arm, which even bothered her during ball tosses for serves. She said afterward she was surprised that the top-seeded Stosur kept hitting to her forehand even after the visit from the trainer.
''She started kind of running around her backhand a little bit more, which is pretty unusual for Caroline to want to do that. So I kind of thought, `OK, there's something going on,''' Stosur said.
As for why she had trouble taking control of the match, Stosur replied: ''Sometimes it's quite difficult playing somebody who's injured.''
The match was played on a secondary grandstand court, instead of in the hard-court tournament's main stadium, which gets more men's matches than women's matches during the joint event.
''I notice there's not too many matches on center court for the women, unfortunately,'' Stosur said when asked by a reporter about the scheduling. ''It'd be nice if we were kind of 50-50 on center court, that's for sure.''
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