Defending champion Serena Williams was knocked out of the third round of the Australian Open on Friday by Slovakian Daniela Hantuchova 6-1, 7-6.

Hantuchova raced through the first set in 31 minutes then regained her composure after Williams saved three match points to force the second set into a tiebreak.

Williams, who had staged a series of miraculous comebacks to win last year's Australian Open, threatened another when she led 4-3 in the tiebreak but Hantuchova held her nerve to clinch it 7-5.

Hantuchova will play Russia's Maria Sharapova in the fourth round after the fourth seed beat Croatia's Jelena Kostanic 6-0, 6-1.