|Federer, the world number two, is two wins away from a record-equalling fifth title at the year-end showpiece [AFP]
Roger Federer and Andy Murray avoided the need for fiddly mathematics as they both produced dominant displays to qualify for the semi-finals of the ATP World Tour Finals.
World number two Federer topped Group B with a classy 7-6 6-3 victory on Thursday over Sweden's Robin Soderling in front of another near-capacity crowd at the 17,500-seat O2 Arena before Murray joined him as runner-up by beating David Ferrer 6-2 6-2.
Federer's three victories mean the 16-times grand slam champion is two wins away from a record-equalling fifth title at the year-end showpiece and a $1.6 million jackpot for winning the tournament undefeated.
They will learn who they meet in Saturday's semi-finals on Friday when Group A concludes with undefeated world number one Rafael Nadal taking on Czech Tomas Berdych and Novak Djokovic up against winless Andy Roddick.
"So far it's been good," the 29-year-old Federer told reporters after following up impressive wins against Ferrer and Murray by beating Soderling, the man who stopped him in his tracks in the quarter-finals of the French Open this year.
"I won against top 10 players in straight sets. That's going to make me feel obviously awfully good for the weekend. But I hope I can keep it up. The tournament's not over yet. This is really when it starts for me."
Error of judgement
Federer and Murray were in the same group in London last year when calculators were needed to work out the top two places and Murray missed out by a game to Juan Martin del Potro.
Mercifully it proved simpler this time with Federer gaining the solitary set he required to progress from Group B courtesy of a crucial error of judgement by Soderling.
Leading 6-5 in the tiebreak Federer found himself pinned in the corner by a meaty Soderling forehand and could only float back a defencive backhand which looked ripe for the picking.
However, Soderling elected to leave it, thinking the ball was heading out. To his horror it landed on the sideline.
Federer in full flow hardly needs Lady Luck on his side but he got another slice of fortune in the first game of the second set when he challenged a Soderling winner on break point down.
The thumping "heartbeat" sound effect reverberated around the darkened O2 Arena as the fans and players waited for Hawkeye's video verdict which revealed that Soderling's effort had missed by a fraction.
That proved the end of Soderling's challenge and his hopes of reaching the semi-finals.
"I think against a player like Roger you need to have a little bit of luck to win," Soderling told reporters. "I definitely didn't have the luck on my side today."
Federer's victory meant Murray knew the scenarios before walking out on court against Ferrer.
Needing to win just one set to finish runner-up, the Briton gave his fans some anxious moments when he lost the first two games against a fired-up opponent before waking up and reeling off the next six.
Murray claimed victory in little more than an hour and was much sharper than he was during a lacklustre defeat by Federer on Tuesday, although he was quick to play down his chances of winning the title, especially if Nadal awaits in the semis.
"I'll try and win. But I'm not sure I've got a whole lot of chance if I play against him," Murray, who will move back above Soderling to fourth in the rankings, told reporters.