TENNIS/Australian Open Championships: Nikolay Davydenko played it safe and paid the price. Having drawn level at one set all and serving for the third the pencil-thin Russian could not force his advantage and the world number one offered him no second chance, winning 6-4, 3-6, 7-6, 7-6.
This was not one of Federer's more lucid performances and, in his moment of crisis, his coach Tony Roche was reduced to staring at his feet and his girlfriend Mirka to biting her nails.
His opponent in tomorrow's semi-final Nicolas Kiefer, having won his quarter-final against Sebastien Grosjean in five sets, will have watched with some hope.
Kiefer, who will be playing in his first grand slam semi-final, knows the odds are against him but at least Federer has shown vulnerability in his past two matches, with Tommy Haas, another German, taking him to five sets in the fourth round.
"These are the moments you practise for, the reason why you work so hard both on and off the court," said Kiefer.
"Me and Roger had close matches last year."
Close they may have been, with Kiefer taking a set off Federer at Wimbledon and the US Open last year, but he has nevertheless lost his last six matches against the Swiss.
There is no doubting the 28-year-old German's talent - he rose to number four in the world six years ago - but he is moody and inconsistent.
His 6-3, 0-6, 6-4, 6-7, 8-6 win yesterday was typically fractious, with Kiefer once throwing his racket across court as Grosjean was about to kill off a point which he subsequently missed.
Grosjean protested, the supervisor Mike Morrissey ruled that the incident had not hindered Grosjean but fortunately the Frenchman went on to hold serve.
To beat Federer it is essential to remain aggressive, within the rules, and this Davydenko tried to do, succeeding in the second set but crucially staying his hand in the third.
The world number five had battled through 18 sets in four matches and grew tired at the end.
"He played well even though maybe he was tired. He did not let me play the way I wanted and should have won the third set," said Federer. "When I saw the draw, I was a little bit worried."
This was, however, Federer's seventh successive win over the Russian, so his concerns were perhaps not all that great.
"It's going to be tough against Kiefer too," he said.
Nobody was inclined to agree - except, of course, Kiefer.
The first men's semi-final between David Nalbandian of Argentina and surprise package Marcos Baghdatis of Cyprus takes place today.
Guardian Service
MEN'S SINGLES
Quarter-finals: (1) Roger Federer (Swi) bt (5) Nikolay Davydenko (Rus) 6-4 3-6 7-6 (9-7) 7-6 (7-5), (21) Nicolas Kiefer (Ger) bt (25) Sebastien Grosjean (Fra) 6-3 0-6 6-4 6-7 (1-7) 8-6.
WOMEN'S SINGLES
Quarter-finals: (3) Amelie Mauresmo (Fra) bt (7) Patty Schnyder (Swi) 6-3 6-0, (2) Kim Clijsters (Bel) bt Martina Hingis (Swi) 6-3 2-6 6-4.
MEN'S DOUBLES
Quarter-finals: (1) Bob Bryan (USA) and Michael Bryan (USA) bt Jan Hernych (Cze) and Ivo Karlovic (Cro) 6-3 3-6 6-1, (4) Paul Hanley (Aus) and Kevin Ullyett (Zim) bt (8) Simon Aspelin (Swe) and Todd Perry (Aus) 6-3 4-6 6-3.
WOMEN'S DOUBLES
Semi-finals: (1) Lisa Raymond (USA) and Samantha Stosur (Aus) bt (5) Anna-Lena Groenefeld (Ger) and Meghann Shaughnessy (USA) 6-2 6-4, (12) Zi Yan (Chn) and Jie Zheng (Chn) bt (9) Shinobu Asagoe (Jpn) and Katarina Srebotnik (Slo) 6-2 7-6 (7-2).
MIXED DOUBLES
Quarter-final: (6) Daniel Nestor (Can) and Elena Likhovtseva (Rus) bt (3) Bob Bryan (USA) and Vera Zvonareva (Rus) 6-4 6-4.
