Serena the cat shows her claws

Serena Williams opted for more traditional dress - a pink top and black shorts - in place of that black Lycra number, and the score was pretty traditional, too, as she moved into the last 16 by beating Nathalie Dechy 6-1 6-1 in 49 minutes.

Williams, on course for another grand slam final showdown with her older sister and defending US Open champion Venus, will next meet twentieth-seeded Czech Daja Bedanova. 'I'm just getting better,' said Serena. 'It's definitely how I like to see things. You can't just stay at the same level or else you won't win a grand slam. 'I don't think I would have won any if I had stayed at the same level. You have to get better as each match goes on.

'My confidence is back, I'm believing in myself. I mean it's not that I've lost confidence, it's just that I was having some tough practices,' she added. 'I'm ready right now to play the final. I was ready yesterday and I'll be ready tomorrow. So, with me, bring it on.'

For the first time in three matches at Flushing Meadows, there was more attention paid to Williams's game than to what she was wearing, although her choice of attire continued to set the tongues wagging.

She explained that her outfits were much more than attention grabbers. The designs also had an impact on her performance. 'This is strawberry ice,' said Serena, explaining her latest kit. 'At the French Open I had an outfit that I just didn't feel serious in the first two days, the little soccer outfit.

'It was really cute, I felt like a schoolgirl but I didn't feel serious in it. But the catsuit, I feel like a cat. I can go fast. I feel really, really serious in that outfit. Especially when I play at night, it's like a cat. I move really fast in that suit... watch out. I'm a firm believer that if you look bad on court you won't play well.'

When asked who would top tennis's 'worst dressed list', the world number one would not take the bait. 'Good try,' she said, laughing.

Martina Navratilova, 45, teamed up with Leander Paes of India to beat top-seeded mixed doubles pair Rennae Stubbs and Todd Woodbridge of Australia 7-6 7-5.