Serena Williams stormed into the women's singles semi-finals of the Australian Open on Tuesday, thrashing second seed Amelie Mauresmo 6-2, 6-2.

Serena said she had nothing to prove, even though it is now 18 months since she last won a grand slam title.

Her sister Venus, without a grand slam title since Wimbledon in 2001, was beaten in the fourth round at Melbourne Park but an angry Serena said that claims the Williams sisters are in decline were unfair.

"I don't appreciate that language, to be honest with you," she said.

"I'm tired of not saying anything, but that's not fair. We've been practising really hard. We've had some serious injuries.

"I mean, I've had surgery. And after surgery, I got to the finals of Wimbledon. I don't know too many people that have done that." she added.