Two women in reach of the world No.1 ranking, Maria Sharapova and Petra Kvitova, will both take on unseeded opponents in Australian Open quarter-finals on Wednesday.

Fourth seed Sharapova, who won the Open in 2008, will meet fellow Russian Ekaterina Makarova, who beat US star Serena Williams in straight sets in the previous round.

Second-seeded Czech Kvitova will meet Italian Sara Errani.

Sharapova, Kvitova and Belarusian Victoria Azarenka are all battling for the No.1 spot, which will be vacated by Caroline Wozniacki after her quarter-final exit on Tuesday.

Wozniacki was ousted by reigning champion Kim Clijsters, who will meet third seed Azarenka in a semi-final.

Long-time rivals Roger Federer and Rafael Nadal will meet in a men’s semi-final.

The make-up of the other men’s semi-final will also be decided on Wednesday.

British hope Andy Murray, the fourth seed and losing finalist of the past two years, will take on Japan’s 24th seed Kei Nishikori in one quarter-final.

World No.1 Novak Djokovic, who defeated Australia’s last hope Lleyton Hewitt in four sets in the fourth round, will meet Spanish fifth seed David Ferrer in the other on Wednesday night.

Ferrer made the Open semi-finals last year, his passage made easier when he beat fellow Spaniard Nadal in the quarter-finals, when Nadal was badly hampered by injury.