By Nick Mulvenney

SYDNEY (Reuters) - Kim Clijsters came through a major test of her early season form to reach the Sydney International final with a 4-6 6-3 7-6 victory over Alisa Kleybanova on Thursday.

The 27-year-old Belgian is favorite for the Australian Open but required all of her expertise at winning clutch points in a ding-dong battle with the big-hitting Russian at a windy Sydney Olympic Park.

The U.S. Open champion clinched her place in the final in the third set tiebreak after a hard-fought two hours and 38 minutes, maintaining her record of not having lost a semi-final or final since coming out of retirement in 2009.

"It probably wasn't my best tennis but I had to work for it really hard," said Clijsters, the Sydney champion in 2003 and 2007.

"I think that's something that's also part the of preparation ...

"Play that work tennis, where you have to just keep fighting, and even if you're not playing your best, or if you're not always able to play your own game, or the way that you would like to play ... and just try to work your way through points and through matches like that."

In Friday's final, Clijsters will meet China's Li Na, who continues to suggest she might match or even better last year's breakthrough at Melbourne Park.

The 28-year-old, who made it to the semi-finals at the year's first grand slam in 2010, came back from a break down in the first set to beat Serbian teenager Bojana Jovanovski 7-6 6-3.

"It wasn't easy, she's young but she's playing well," said Li, who was at a loss to explain her great start to the year.

"I just came in, and then finally I was in the final. I was surprised. I always play well in Australia. I don't know why."

Former top 10 player Gilles Simon continued his battle back from a serious knee injury to reach the last four in the men's tournament with a 6-4 6-3 win over Ukrainian Alexandr Dolgopolov on a windy day at the Sydney Olympic Park.


The French baseline hustler, who was ranked as high as sixth in the world at the start of 2009 after beating Roger Federer, Rafa Nadal and Novak Djokovic in 2008, said his mobility was improving.

"My physical trainer is 47-years-old, and when we were running he was faster than me," he said. "He's still fit, but still, I was one of the fastest player on the tour.

"Trust me, I'm moving far better now than three or four months ago."

His semi-final opponent Ernest Gulbis was, by contrast, feeling terrible after his 6-4 6-4 quarter-final victory over another Ukrainian, Sergiy Stakhovsky.

"Bad," the Latvian said when asked how he felt. "Yesterday's match killed me physically. It was really humid and I lost a lot fluids, so straight I went to the hotel and I went to sleep. I didn't feel good.

"Going to be okay tomorrow. I just can't go really long matches. Don't tell Simon," he added, with a laugh.

Serbian Viktor Troicki later beat Frenchman Richard Gasquet 6-4 6-4 to set up a last four meeting with German Florian Mayer, who surged past Italian Potito Starace 6-4 6-1.

(Editing by Peter Rutherford and Pritha Sarkar)