Off-form Sharapova Through

Maria Sharapova overcame a spirited performance by compatriot Nadia Petrova to book a place in the semi-finals in Melbourne.

The world No4 will now face the winner of the clash between top seed Lindsay Davenport and Justine Henin-Hardenne.

The match was notable for the copious number of errors both players committed rather than the style of the tennis, but a gritty fightback by the tournament’s fourth seed eventually saw her home 7-6 (8-6), 6-4 after Petrova failed to capitalize on numerous chances.

In the men’s competition, meanwhile, David Nalbandian is fast shaping up to be the biggest challenger to world No1 Roger Federer here.

Nalbandian, the highest remaining seed in the opposite half of the draw to Federer, booked the first spot in the semi-finals - his first at the Australian Open - after overcoming Fabrice Santoro 7-5, 6-0, 6-0.

The match on Rod Laver Arena was a clash of two different styles as Nalbandian, the powerful baseliner, locked horns with Santoro, the mercurial ball-player.

However, it eventually proved to be Nalbandian’s day as he overcame an initial challenge from his opponent before racing away with the victory.

The Argentine currently boasts a winning record against Federer and won their most recent encounter at the final of the Masters Cup in Shanghai at the end of 2005.

However, the tournament’s fourth seed will have to get to the final via Ivan Ljubicic or Marcos Baghdatis.