LONDON — Juan Martin del Potro beat Roger Federer 7-6, 4-6, 6-3 to reach the semifinals of the ATP World Tour Finals Saturday. The Argentine guaranteed himself one of the top two places in Group B with a 2-1 record, the same as defending champion Federer who had already sealed a semifinal spot after winning his opening two round-robin matches at the season-ending tournament. “I'm so happy to beat Roger once again, I know he's a favorite here but the crowd respected me also,” Del Potro said. “I was a little lucky toward the end of the match. Always when you beat these kinds of players you need luck on your side but I played well. “I took the break-point chances in the last set, then I served really well in the last game. I was very nervous but I closed out the match. It's going to be a tough match against Djokovic or Murray, but I'm so excited to get into the semis.” The final day of action in Group B began with seven scenarios, but a three-set win for world No. 7 Del Potro muddied the waters as the lineup for the semifinals will now not be known until after the evening match between David Ferrer and Janko Tipsarevic. Victory for Tipsarevic would see Del Potro top the group while a win for Ferrer would mean three players are tied on two wins and in that case Federer would top the group because of his superior sets percentage and Del Potro would be runner-up. Ferrer had been relying on a Federer victory to keep his hopes of a semifinal place alive. The winner of the group will face Britain's Andy Murray while the runner-up will play world number Novak Djokovic. On Friday, Murray reached the semifinals when he completed his Group A matches with a 6-2, 7-6 victory over Jo-Wilfried Tsonga. Frenchman Tsonga, despite losing his opening two round-robin matches, could have reached the semis at Murray's expense with a straight sets win but a loose start scuppered any hope. Murray surged into a 4-0 lead as a languid Tsonga gifted the Scot two service breaks with a rash of unforced errors. Tsonga finally got off the mark in the fifth game but it did little to alter the flow of the match as US Open champion Murray wrapped up the opening set in 33 minutes. Two double faults from Tsonga helped Murray break serve at the start of the second. Murray appeared to lose focus when he allowed Tsonga to break to love and level at 4-4. Another sell-out crowd at the famous London venue were treated to some entertaining rallies as Tsonga, with nothing to lose, went for broke but Murray avoided using up any extra energy when he claimed a second set tiebreak 7-3. Paes and Stepanek win India's Leander Paes and his Czech partner Radek Stepanek enjoyed a surprise 6-4, 6-7 (6-8), 10-7 win over the top seeded Bryan brothers to clinch first place in Group A at the ATP Tour Finals Saturday. Paes and Stepanek had already booked their place in Sunday's semifinals after winning their opening two group fixtures, but they didn't take it easy against Bob and Mike Bryan at London's O2 Arena. After winning a tight first set, the pair were pegged back in the second, which the Americans won on a tie-break. That meant a super tie-break was needed to settle the match and Paes and Stepanek took it on their second match point. Paes and Stepanek's victory gives them the only 100 percent record of the eight doubles teams competing at the season-ending event and means they will play India's Mahesh Bhupathi and Rohan Bopanna in the semifinals. That promises to be a bitter battle after Bhupathi refused to be partnered with Paes during the London Olympics earlier this year. Bhupathi and Paes had a successful doubles partnership for several years, but split up when their relationship deteriorated. — Agencies
