Champion Serena Williams [Images] was unceremoniously bundled out of the Australian Open quarter-finals by third-seeded Serb Jelena Jankovic in Melbourne on Tuesday.

Williams was seeking to become the first women's champion to defend her Australian title since Jennifer Capriati [Images] in 2002.

"It was an unbelievable match and I'm still shaking," Jankovic said in a courtside interview after the 6-3, 6-4 victory.

• Images: Melbourne Snapshots

"I'm really so happy to be in the semis for the first time in Australia. I came here with no expectations and it is amazing to beat the defending champion.

"It doesn't happen every day."

A sluggish Williams, who was unseeded when she won the tournament last year, broke the world number four in the second game of the opening quarter-final on Rod Laver Arena but then went to pieces.

• Bhupathi rejected offer to throw match

Jankovic broke back immediately and held to level the score at 2-2 and the pair then engaged in a tit-for-tat contest achieving break points only for their opponent to battle back.

Both had seven opportunists each in the first set, but the seventh-seeded Williams was unable to convert any after the initial break while Jankovic took three of hers to win the first set 6-3 on Williams's service.

BLUDGEON SHOTS

Jankovic then jumped out to a 2-0 lead in the second set, before the pair again engaged in breaking each other's serve.

Williams finally held at 3-3 after a game that involved six deuce points before Jankovic held in the next game after a struggle that again ebbed between deuce and advantage points.

Jankovic had the opportunity to serve for the match at 5-3 up only for Williams to bludgeon shots from all parts of the court and break back.

The drama, however, was not finished with Jankovic battling back from 40-15 down on Williams's serve to snatch the match in 99 minutes when Willams's groundstroke sailed wide.

She will now meet the winner of the quarter-final between world number one Justine Henin [Images] and fifth-seed Maria Sharapova [Images], who play later on Tuesday.