To beat one Williams sister in a grand-slam tournament takes some mettle, to complete the family set in the space of two matches is an exceptional achievement. It has happened only twice and on both occasions it has required the skills of the best player in the world at the time to master the clan.

In 2001, at the Australian Open, Martina Hingis, of Switzerland, defeated Serena in the quarter-finals and Venus in the last four. Yesterday, on the Arthur Ashe Stadium court, Justine Henin snuffed out Venus’s attempt to avenge her little sister’s defeat on Tuesday night.

The Belgian won 7-6, 6-4, finally stopping a sequence of seven successive defeats against the elder sister, who required her pulse to be taken three games before the end of a match played in extreme humidity.

At least this match had a pulse. The first semi-final, won 3-6, 6-1, 6-1 by Svetlana Kuznetsova over Anna Chakvetadze, her Russian compatriot, was a festival of frustration, with so many errors it became impossible to keep up with them. There was the ridiculous sight, also, of both players leaving the court at the end of the second set, utilising the extreme heat rule (at 82F, 28C, if both players desire, they can have a ten-minute break). The effect was for a third of the audience to leave and spend the third set stocking up on food rather than watch this onslaught of errors.

Kuznetsova, the 2004 champion here, is into her third grand-slam tournament final and will become the No 2 player in the world when the new rankings are announced. She did not play like it yesterday and was gifted a route back into the match when Chakvetadze began to play as apallingly in the second and third sets as Kuznetsova had done in the first.

Into the semi-finals of his fourteenth grand-slam tournament in succession - Roger Federer today faces Nikolay Davydenko, of Russia, at this stage for the third time in the past five majors - with nine hours of court time under his belt - far less than Davydenko, Novak Djokovic and David Ferrer, his fellow survivors - the Swiss is the epitome of vitality, allowing him to think long term.

In draining the confidence from his opponents - and Andy Roddick’s verbal trashing of the locker-room after his US Open quarter-final defeat in the early hours of Thursday could be heard through its thick walls - Federer simply replenishes his own. How long can this continue? Five years? Ten? He is 26 and said this week: “I thought of the figure 35 [to continue until that age] as a goal.

“Minimally, I would like to continue until the Olympic Games of 2012 in London. But basically, I would like to play tennis as long as possible and I believe it is realistic to play until 35. Maybe I would not play 20 to 25 tournaments then any more, only ten to 15, but I also think that it would be good for the tour if I stick to the game for as long as possible.

“Of course, I need to stay healthy as well. Who knows, maybe that [a lack of motivation] will come one day, maybe I’ll be tired of all this travelling, but right now, the years pass extremely quickly. It’s crazy, we already have the last major of the season again. I feel as if I was still playing the juniors a very short time ago, I can still recall all the results from those days.”

Djokovic is loving this tournament. At the conclusion of his victory over Carlos Moyà, the 20-year-old Serb was asked if he might give the crowd a few snippets from his repertoire of impersonations of his fellow players. And so Rafael Nadal, Roddick and, yes, Maria Sharapova came back to life before our very eyes. This boy is something.