TENNIS/US Open: Andy Murray's second-round victory over Roger Federer at the Cincinnati Masters, only the world number one's fifth defeat this season - the rest all by Rafael Nadal - substantially raised the British teenager's profile in the United States and swung the rumour mills into frenzied motion.

Was there something wrong with Federer? Was he carrying an injury, or were there some unsuspected off-court problems? It was even suggested that the Swiss was human.

High-powered microscopes have been scanning Federer for the last 12 days at the US Open, searching for hairline cracks in his confidence, and there were occasional moments in his quarter-final against James Blake when perfection was sullied. The American could have won the opening set.

He might have taken the match to five sets. But he didn't, and so for the third successive year Federer reached Super Saturday, beating the American 7-6, 6-0, 6-7, 6-4.

Blake, a former Harvard student, was asked to deliver a 100-word resume on Federer, whom he has now failed to beat in five meetings, although this time he did finally manage to take a set.

"There are just too many things he does well. He doesn't panic. He plays offence unbelievably well. He plays defence better than anyone I've ever played. He makes so many gets, and he doesn't just put it back, he puts it where it's difficult for you to hit the next shot.

"Volleys well. Serves well. Handled the pressure of being number one in the world. Handled the pressure of being against a crowd tonight that was clearly on my side. Got the biggest forehand in the game. Seems to be able to create pace out of nothing. That's 100 words? I could keep going."

Nobody doubted he could. Insert any name in the place of Blake and the message would be pretty much the same. The man is a genius.

Standing between Federer and his 10th grand slam final - and he has won eight - today is the unassuming figure of Nikolay Davydenko, a Ukraine-born German-based Russian citizen. He easily defeated Murray in the fourth round and yesterday knocked out Tommy Haas in five sets.

He is not a big man, yet exceptional speed and endurance has seen him rise to world number six and reach last year's French Open semi-finals, his previous best slam performance.

"He's really improved on hard courts. We all knew he could play on clay, but all of a sudden he found another gear. Every part of his game has improved because his serve was pretty dodgy," said Federer, who is always, with no hint of being patronising, inclined to see the best in opponents.

Head-to-heads usually tell a different tale; in theirs, Federer leads Davydenko 7-0. "You need to think you can beat him," said the 25-year-old Davydenko.

In the other semi-final, Andy Roddick, showing fresh confidence and purpose under Jimmy Connors, plays another Russian, Mikhail Youzhny.

This is unknown territory for Youzhny, whereas Roddick won his one slam here in 2003, the year before Federer laid sole claim to this title.

"It was a completely different scenario then," Roddick said of his Open triumph. "It was all new and exciting. I hadn't really had anything tough in my career yet. I kind of shot up real quick and then had a hot summer.

"Maybe I didn't realise what was going on. I think now maybe it's a bit more gratifying. I'm really excited."

Whoever wins that one, Federer will doubtless have kind words before tomorrow night's final. But his record against Youzhny is 7-0 and he leads Roddick 10-1.

A ninth slam beckons.

Guardian Service