MONTREAL (Reuters) - An injured Kim Clijsters hobbled to a 2-6 6-3 6-2 quarter-final loss to Vera Zvonareva at the Montreal Cup on Friday, casting doubt on the Belgian's ability to defend her U.S. Open crown.
Clijsters later played down the injury she described as tightness in her left hip, saying she will undergo an MRI next week to make sure it is nothing serious.
The Belgian made it clear she intends to be Flushing Meadows to launch her title defense.
"Don't worry, there's no doubt in my mind (I will be at the U.S. Open)," Clijsters told reporters. "Maybe I will have to take precautions but a lot of girls these day play with tape to protect themselves.
"It doesn't mean you can't compete."
Clijsters appeared to hurt her hip in the second set and Zvonareva pounced, sweeping through nine straight games on her way to taking a spot in the last four.
Despite being unable to chase down shots, the battling Belgian refused to retire and rallied from 5-0 down in the third before Zvonareva finished her off with a service break.
"I don't like to give up," said Clijsters, who also lost to Zvonareva in the Wimbledon quarter-finals. "I was still able to move, I was still able to hit the ball so I didn't want to quit.
"I'm not blaming my injury. I also lost to her (Zvonareva) at Wimbledon where I was feeling totally fine."
The world number four had gotten her quarter-final off to a fast start, breaking Zvonareva at the first opportunity to jump out to a 3-0 lead. She then broke the eighth-seeded Russian again to take the opening set.
But Clijsters, previously unbeaten in seven matches on North American hardcourts this summer, began to show signs of a problem late in the second as Zvonareva raced through the last four games, breaking the Belgian twice to level the match.
After calling for the trainer and receiving treatment during the changeover, the fifth-seeded Clijsters asked for a medical time out and exited the court. When she returned it was with her left thigh heavily strapped.
"It wasn't one shot or one movement that made something change," said Clijsters, who first began feeling discomfort during her opening match against American Bethanie Mattek-Sands. "It was something that just gradually got tighter and tighter.
"The one thing I'm relieved about is it wasn't something that just shot in there.
"I just wanted it strapped a little tighter."
Earlier, Svetlana Kuznetsova thrashed China's Zheng Jie 6-1 6-3 to book her semi-final place.
Kuznetsova, the first Russian woman to win the U.S. Open, put together a solid build-up to Flushing Meadows having claimed her 13th career title in San Diego two weeks ago.
The world number 16 has moved into the last four in Montreal for the first time in seven visits to Canada.
Editing by Steve Ginsburg