Rafael Nadal reached the semi-finals of the Australian Open by beating Gilles Simon 6-2, 7-5, 7-5 today - and then admitted he had been apprehensive about playing the Frenchman.

Although the world No1 has not dropped a set in Melbourne, he did lose his last meeting against the sixth seed, at the Madrid Masters in October.

"I was coming to the match with some doubts," said Nadal, who despite his straight-sets victory was not at his best. "I don't know how I won, really. Gilles is very good player, much improved in last few months."

Nadal will face Fernando Verdasco in Friday's semi-final after his Spanish compatriot beat last year's runner-up JoWilfried Tsonga, 7-6, 3-6, 6-3, 62.

The 14th seed, who knocked out Andy Murray is not afraid of facing Nadal. and said: "Playing him is the toughest match possible. I'm feeling pretty good, and I just think I can beat anyone. But, you know, the same way that I can win, I can lose.

"I'm playing with the best players in the world so of course they are always tough matches."

Svetlana Kuznetsova was furious following her 5-7, 7-5, 6-1 quarterfinal defeat to second seed Serena Williams.

The Russian was a set up against the American, who was struggling as temperatures hit 110°F, when play was halted and the Rod Laver Arena roof closed following the use of the extreme-heat policy.

Kuznetsova, seeded eight, said: "I was definitely angry. The game was going my way. It's two different games. One you play inside, one you play outside."

Williams now plays Russian No4 seed Elena Dementieva, who beat the world No46 Carla Suarez Navarro, of Spain, 6-2, 6-2.