Nicole Vaidisova, at 17 the youngest player left in the singles at the Australian Open, faces Lucie Safarova in the last eight

Lucie Safarova, who knocked out Amelie Mauresmo, is given the run-around by her Czech compatriot in the opening set

And it is 10th seed Vaidisova who is the first to reach the last four in Melbourne with a straight sets win 6-1 6-4

Two-time champion Serena Williams takes a while to get going in her quarter-final match against Israel's Shahar Peer

Sixteenth seed Peer, in her first Grand Slam quarter-final, takes advantage of a flat Williams and takes the opening set

But two-time former champion Williams shows real fight to clinch an enthralling victory, winning 8-6 in the final set

Ex-world number one Andy Roddick is in awesome form in his quarter-final against fellow American Mardy Fish

Sixth seed Roddick hands his friend and former room-mate a 6-2 6-2 6-2 mauling in just one hour and 27 minutes

Tommy Robredo, who has never beaten Roger Federer in six attempts, loses the first set to the defending champion

The world no.1 is well below his best and Robredo tries to take advantage but Federer still wins the second set

Federer wraps up victory in the third set to see off Robredo and sets up a clash with Andy Roddick in the semi-finals