36 unforced errors doom Williams

MELBOURNE, Australia -- Defending champion Serena Williams slumped out of the Australian Open in a 6-3, 6-4 quarterfinal loss to third-ranked Jelena Jankovic on Tuesday.

Williams, who was unseeded and ranked No. 81 when she won here last year for her eighth Grand Slam title, struggled with her serve and made 36 unforced errors trying to combat Jankovic's go-for-broke game.

Williams had not dropped a set in her four previous matches, but she dropped serve twice in the opening set.

Jankovic broke Williams and served for the match at 5-3, only to be broken herself. Williams led 40-15 in the next game only to fall apart again, double-faulting to set up match point, then sending a forehand wide.

"It was an unbelievable match, I am still shaking," said Jankovic, reaching the semifinals for the first time at Melbourne Park and only the third time at a major. "I am so happy.

"I came here with no expectations -- it's amazing to beat the defending champion and in general a champion like Serena, it doesn't happen every day."

Jankovic had to fend off 3 match points in the third set of her first-round match, which included 15 service breaks, before edging Tamira Paszek, 2-6, 6-2, 12-10.

She followed that with straight-sets wins over Edina Gallovits and Casey Dellacqua and was taken to three sets by No. 30 Virginie Razzano.

After taking the first two games, Williams became increasingly sluggish. Normally bouncing on the balls of her feet and renowned for never giving up on a ball, she was often caught flatfooted, left to watch as Jankovic's shots landed for winners or to whack unforced errors awkwardly into the net.

Top-ranked Justine Henin was to play No. 5 Maria Sharapova, the losing finalist last year, on Tuesday night.