Australian Open: Williams and Federer through to semi-finals

Serena Williams and Roger Federer are the first of the big stars through to the semi-finals of the Australian Open.

Federer beat Tomas Berdych in straight sets 7-6, 6-2, 6-4.

He could face world number one Novak Djokovic in the next round on Thursday.

Serena Williams beat Maria Sharapova 6-4, 6-1.

She's aiming for her 22nd Grand Slam title by winning this tournament.

Williams will take on Poland's Agnieszka Radwanska in her semi-final.