Sloane Stephens stuns ailing Serena Williams to set up Victoria Azarenka Australian Open semi-final

Sloane Stephens of the US celebrates at match point (EPA)

Sloane Stephens, who grew up with pictures of Serena Williams on her bedroom wall, produced the biggest shock of the Australian Open so far when she beat the 15-times Grand Slam champion in the quarter-finals here today.

Williams, who has been a mentor to Stephens in recent years, hurt her back towards the end of the second set and struggled for the rest of the match before losing 3-6, 7-5, 6-4.

Williams, five times a champion here, had been the red-hot favourite to win her third Grand Slam title in succession but admitted after this defeat that she had experienced “a tough two weeks”, having also had to cope with an ankle problem.

Stephens, who now meets Victoria Azarenka, a 7-5, 6-1 winner over Svetlana Kuznetsova, in tomorrow’s semi-finals, showed few nerves in the biggest match of her life. “I just didn't have anything to lose,” she said.  “You're playing for the semis of a Grand Slam.  You just got to go out and do it.”