Forgetful Serena in Cruise Control During Win Over Peng

So naturally and rapidly has Serena Williams re-assumed the mantle of the world's leading player that some of her rivals are falling over before she gets to them and her biggest difficulties appear to be an oddly failing memory and getting her stretch limo through the traffic jams..

The younger Williams sister, who will break Steffi Graf's record of five titles at the Sony Ericsson Open if she wins in Miami this year, almost absent-mindedly reached the fourth round following tribulations such as deficits, rain delays and late night questions, which might have had many less mentally tougher players fretting.

Serena came from 1-3 down and within three points of losing the first set against China's Peng Shuai, and had to hang around for 45 minutes mid-match while the evening drizzle did its best to antagonize everyone, before eventually cantering through 7-5, 6-2.

She managed it only by getting a trickle of errors similarly to dry up. Williams nevertheless gave the impression she couldn't recall much about it. "I don't even remember being 5-4 down to be honest," she said. "Obviously I must have been concerned, but until my hitter [Sacha Bajin] was like, you were down 5-4, I didn't remember.

Asked which of her five title-winning years in Miami were most spectacular, she replied dreamily: "It's too late you know, I don't quite remember," before suggesting that one year "the traffic was so much, it was from the toll booth all the way down to the tennis, and that stood out for me."

It is true that the three times US Open champion has been that popular, and, despite the hiatuses in her success, remains so. She is using this to help promote her own jewelery line in which everything costs less than a hundred dollars, so that, allegedly, "at a trying time like this everyone can look gorgeous and still be affordable."

Ana Ivanovic, Dinara Safina and Jelena Jankovic have all mysteriously lost early and can start preparing for the European clay court season, where they stand a better chance of beating Williams. It leaves only Venus Williams, whom Serena should play in the semi-finals, as her only remaining plausible rival this week. The last time she lost here to anyone other than her elder sister was eight years ago.

The men's US Open champion, Roger Federer, has looked smooth and calm but still a little subdued, whilst winning two matches in straight sets, and earning a quarter-final spot against one of his more remarkable opponents.

Federer faces Taylor Dent, an American once remembered as the promising son of a former Australian Davis Cup player Phil Dent, and as one of the few remaining serve-volleyers. Now he is the maker of one of the most remarkable comebacks of all, having had two spinal fusion surgeries and worn a body cast, 23 hours a day for nine months, hardly able to move, in proving wrong those who said he would never play again. He will be motivated.