If Serena Williams does not win the US Open here next weekend it will be one of the biggest surprises in the sport since Tim Henman's great grandmother shocked Wimbledon by becoming the first woman to serve overarm at the All England Club 110 years ago.
Williams, who has taken the art of serving to a level that Ellen Stawell-Brown, Henman's ancestor, would not recognise, has been the favourite to win the year's final Grand Slam event ever since she won tournaments in Stanford and Toronto in the summer. The 29-year-old American has not lost on the court since Wimbledon, where she played her second tournament after an 11-month absence through injury and illness, and her main rivals for the title here have been falling fast.
The latest to bow out was brought down by Williams herself. Victoria Azarenka, the world No 5, was the unlucky one in the top group of players to draw Williams in the third round, the American having been seeded No 28 in accordance with her world ranking, which has dropped because she has played so little in the last year. Azarenka won just eight points in losing the first five games in only 17 minutes in Arthur Ashe Stadium on Saturday and, although the 22-year-old from Belarus improved markedly in an excellent second set, Williams won the match 6-1, 7-6.
In the latter stages the two players produced the best tennis seen in the women's tournament so far. Azarenka saved three match points when serving at 3-5 and 0-40 and then broke Williams in the next game, saving another match point along the way. The tie-break was tight, but at 5-5 Azarenka missed two forehands to give Williams the match.
Azarenka described the experience of facing Williams in her current form as "a little bit painful", while her opponent said the quality of the match had made it feel like a semi-final. "I think I played really well," Williams said. "I was doing the right things. It's a good feeling. It feels amazing."
Nevertheless, Williams knows she still has plenty of work to do if she is to win the title here for the first time since 2008. "At the end of the day, it was a third round," she said. "I'm only in the round of 16 now, so I've got to keep going the best I can."
Caroline Wozniacki, the world No 1, is still in the draw and Vera Zvonareva, the No 2, was playing Sabine Lisicki last night, but the top two have yet to win a Grand Slam title between them. Kim Clijsters, the world No 3 and winner here for the last two years, pulled out with injury before the tournament began, while the next four players in the rankings – Maria Sharapova, Azarenka, Li Na (French Open champion) and Petra Kvitova (Wimbledon champion) – have all been knocked out.
Is Williams' superiority over her rivals a reflection of her own brilliance or the poor state of women's tennis? There is probably some truth in the latter, but Williams' excellence should not be underestimated. Some of her play on Saturday, against a fine opponent, was stunning.
Williams' serve, struck at speeds of up to 117mph, was awesome in its weight and precision. Azarenka could draw consolation from becoming the first player to break the former world No 1 in the tournament, but Williams hit 12 aces against an opponent reckoned to have one of the best returns in the game.
The American is on course to win her 13th Grand slam title only six months after being rushed to hospital with a blood clot in her lung, having initially seen doctors for treatment on the foot injury that had kept her out of the game since last year's Wimbledon. "I thought she was going to die," Richard Williams, her father, admitted on Saturday. "I don't even know how she lived through it."
Williams herself said of the experience: "I actually was really calm. I didn't want to alert my parents or my family or anything. I got really, really, really calm and just like relaxed and really easy. I think that's the calmest I've ever been in my life, just trying to be strong for everyone else."
She added: "It puts everything in perspective. I love playing tennis, I love the battle, but I realise that life is so precious and things could be a lot worse. It isn't all about tennis. It's about life."
Williams now plays Ana Ivanovic, who has not gone beyond the fourth round of a Grand Slam since winning the French Open three years ago. The 24-year-old Serb, who is now coached by Britain's Nigel Sears, reached the last 16 by beating Sloane Stephens, of the United States, 6-3, 6-4.