Serena Williams' reign as Australian Open champion is over after Daniela Hantuchova won their third round tie 6-1 7-6 (7-5).
Hantuchova had not previously won more than four games in a set against Serena
Hantuchova had never beaten Williams - and had not even taken a set off the American in three previous matches.
Even a half-hour rain delay in the first set could not explain the display of Williams, who struggled throughout.
Hantuchova wasted three match points on Williams' serve before winning the match with the first on her own serve.
The Slovakian had already taken the upper hand by the time the players were forced off by the rain.
Williams served first and the opening two games went with serve, before Hantuchova claimed the first break of the day in the third game, on her seventh game point.
She then held her serve to lead 3-1 and was 30-15 up in the next when the rain set in.
When play resumed, a forehand winner and a long Williams return saw Hantuchova move 4-1 ahead, the first time she had won that many games in a set against the American.
Williams' play was dotted with unforced errors, and with the court at her mercy, she smashed long to put Hantuchova within one game of taking the set, which she finally wrapped up 6-1 at the third time of asking.
Hantuchova served first in the second set, and although the Slovakian opened with a double fault, more unforced errors by Williams gifted her the game, and suggested it might not be the defending champion's day.
Williams held her serve for 1-1 but a sliced return from a towering Hantuchova backhand return cost her the next game and restored Hantuchova's lead.
The champion then took the next three games to lead for the first time since the opening game of the match, but another error allowed Hantuchova to pull the score back to 4-3.
After a long baseline battle, Hantuchova broke back for 4-4 and held her nerve to move within one game of the biggest result of her life, only for Williams to win two of the next three games and take the game to a tie-break.
Hantuchova raced into a 3-0 lead in the tie-break, before Williams showed the form that made her a champion, pulling it back to 4-3.
A stunning forehand winner by Hantuchova and a long return by Williams gave Hantuchova her fourth match point of the game, all of them on her opponent's serve, but she failed to take it.
But when Hantuchova finally had a match point on her own serve, Williams' return of the serve was wide, and she was out of the tournament.