Federer survives Davydenko test

Federer struggled at times for the second match in succession

Top seed Roger Federer booked his place in the semi-finals of the Australian Open after a fierce four-set battle with fifth seed Nikolay Davydenko.

The world number one produced an error-strewn performance against his tough Russian opponent but eventually won 6-4 3-6 7-6 (9-7) 7-6 (7-5).

Davydenko produced some superb tennis but could not convert six set points in the crucial third set.

Federer edged through the fourth and now meets Nicolas Kiefer.

The Swiss star's victory, in three hours and 13 minutes, ensured a seventh successive Grand Slam semi-final, second only to Ivan Lendl's 10 from 1985-1988.

I always have tough games against Nikolay and this was the same Roger Federer

But after struggling past Tommy Haas in five sets in the previous round there was further evidence that the top seed is vulnerable at the moment.

Federer started well, breaking Davydenko's serve in the eighth game of the opening set, but the Russian broke straight back.

The 24-year-old world number one then raced to three break points in the next game and took the first set when Davydenko's forehand was long.

But he produced a string of inexplicable mistakes as he was broken in the fifth and ninth games, and Davydenko levelled the match by taking the second set 6-3.

The match hinged on a dramatic third set, in which Davydenko broke for a 5-3 lead but fail to serve it out.

Davydenko's next chance came at 6-5 when he held two set points only for the Swiss to hold on again, and the fifth seed then squandered a 6-3 lead in the tie-break.

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The Russian worked his way to another three set points, a total of six, on the back of Federer errors, but was unable to convert any of them, and eventually double-faulted at 8-7.

Both players exchanged service breaks at the start of the fourth set and Federer missed a match point on Davydenko's serve in the 12th game.

But with the match sent into a second tie-break, Federer got to two match points and finally clinched the win on his second with a blistering serve down the middle.

"I always have tough matches against Nikolay and this was the same," Federer admitted afterwards.

"Usually when I scramble it's because of my opponent. It was a fantastic match.

"He plays well on this surface and he definitely pushed me hard, but I still came through."

Davydenko said: "I knew how I needed to play against Federer to beat him, but it was very difficult - too much running, like I did in the first and second and the third set."