Defending champion Roger Federer maintained his 100 per cent record at this year’s ATP World Tour Finals by completing his group fixtures with a 6-1, 3-6, 6-3 victory over America’s Mardy Fish yesterday.

Federer was already guaranteed top spot in Group B and a place in the semi-finals after winning his first two matches and the Swiss survived a mid-match wobble against Fish to extend his fine run in London.

Federer’s 37th career Tour Finals victory moved him into second place on the all-time list ahead of Boris Becker and he is only two wins behind leader Ivan Lendl.

His semi-final opponent is still to be decided, but if Federer can maintain this impressive form it would be no surprise to see him win the tournament for a record sixth time and equal Lendl’s tally of victories in the process.

In contrast, Fish, who was already out of contention for a semi-final spot after losing against Rafael Nadal and Jo-Wilfried Tsonga, ends his first visit to the season finale without a win.

“I didn’t expect anything different from Mardy. He is always very dangerous,” Federer said. “He takes the ball very early, serves great and can get on a roll, so obviously I’m relieved to win.

“It is great to have won all three matches in the group stages. I have had a great run since the US Open and I’m still going strong.”

On Wednesday, world number one Novak Djokovic was beaten for only the fifth time this year as Spain’s David Ferrer booked his place in the semi-finals of the ATP World Tour Finals with a 6-3, 6-1 victory.

Djokovic had won 70 of his previous 74 matches during a majestic campaign, but the Serb was completely outplayed by Ferrer, who joins Federer in the last four.