SYDNEY - World number three Amelie Mauresmo's Australian Open title defence took a hit when she was knocked out of the Sydney International warm-up tournament here.

The top seed crashed out to rising Serbian star Jelena Jankovic 7-5, 6-0 in the quarter-finals on Wednesday, cutting back on her court time ahead of the year's first Grand Slam which starts Monday.

Amelie Mauresmo of France hits a shot to Jelena Jankovic of Serbia during their match at the Sydney International tennis tournament January 10, 2007. [Reuters]

Jankovic won her eighth straight match following her tournament win in New Zealand last weekend, overrunning the French player in hot conditions.

"I'm just disappointed about the way I feel, there is a lot of work to do in my game and physically, and so that's more what I'm concerned about than being out of the tournament," Mauresmo said.

"I would have loved to play one or two more matches, but I still have some work to do.

"I still need to work on the quickness around the court and reaction. It's the final details, which are very important."

Jankovic, a semi-finalist at last year's US Open, followed up her victory over five-time Grand Slam champion Martina Hingis and Australian Samantha Stosur with a comprehensive performance.

"Eight wins in a row. It's unbelievable," 12th-ranked Jankovic said. "I couldn't have asked for a better start to the year. I'm so happy that I beat the number three in the world. It's just great."

Jankovic will play eighth-seeded Czech Nicole Vaidisova in Thursday's semis after Vaidisova overcame Serbian Ana Ivanovic 6-4, 6-2 in a night match.

Meanwhile, Kim Clijsters swept into the semi-finals after a quickfire victory over Israeli Shahar Peer.

The world number five took just 54 minutes to claim a 6-2, 6-1 victory over the 18th-ranked Peer to book a semi-final with China's Li Na on Thursday.

The 21st-ranked Li wore down Slovenia's Katarina Srebotnik in her quarter-final, winning 7-5, 6-1 in 77 minutes, serving at a high 77 percent.

The Belgian third seed claimed 23 winners in breaking Peer's service five times to romp to victory in sweltering conditions.

Clijsters, on her farewell season on the women's tour at the age of 23, said she served the best she has so far on the Australian leg and was working her way into peak form for the Australian Open.

"I served well. I think that was a lot better today than I've been serving so far throughout the whole trip that I've been here. So that's good, gradually getting better and better," Clijsters said.

Clijsters is putting away her racket at the end of the season and is engaged to be married.

The personable Belgian has been taking cooking lessons in preparation for her new life at home, although she did not have the nerve to cook Christmas lunch.

"I had too many people over for Christmas," she said. "I get too nervous when I have to cook in front of a lot of people and I have the pressure, so we ordered a lot of food for Christmas."