The Australian Open will have a new women's champion after Victoria Azarenka joined the purge of the favourites in Melbourne after losing to the impressive Agnieszka Radwanska in the quarter-final. 

Azarenka had not lost at the tournament since 2011, a stretch of 18 matches, but she suffered the indignity of a love set as Radwanska pulled off a 6-1 5-7 6-0 victory.

It is the first time in the Open era that both defending champions have lost in the quarter-finals at the Australian Open.

The women's champion will come from two-time finalist Li Na, 19-year-old Eugenie Bouchard, Radwanska and Slovakia's Dominika Cibulkova, who defeated Simona Halep on Wednesday morning.

Radwanska had only previously made the last four of a grand slam at Wimbledon, where she was beaten by Williams in the final in 2012 and Sabine Lisicki in the semi-finals last year.

She went into Wednesday's match on a seven-match losing streak against Azarenka, who had also won their last 12 sets dating back to a quarter-final meeting here two years ago.

But she was simply outplayed by Radwanska, whose touch and range of shots is unique at the top of the women's game.

Azarenka managed to scrap her way into a decider but there Radwanska was sublime, drawing gasps from the crowd with some of her winners.

Radwanska will be a big favourite to beat Cibulkova and reach the final, but she will remember only too well the strange events of Wimbledon last year.

Then the Pole was by far the highest seed left in the semi-finals only to lose to Lisicki.

Cibulkova followed up her victory over Maria Sharapova by crushing Halep to reach the semi-finals of the Australian Open.

Romanian Halep never found her rhythm and world number 24 Cibulkova took just an hour to triumph 6-3 6-0 on Rod Laver Arena.

The 24-year-old Slovakian's only previous grand slam semi-final came at the French Open in 2009 and she has never made a final.

Her previous best at Melbourne Park had been a fourth-round appearance in the same year but she carried on the form she had shown in upsetting third seed Sharapova in the fourth round.