Wilfried Tsonga earned his first win at the ATP World Tour Finals Tuesday, beating Mardy Fish of the United States 7-6 (4), 6-1 in his second Group B match. Fish was slowed by the left hamstring injury that has disrupted the end of his season, while Tsonga struggled to find consistency. The sixth-seeded Frenchman was twice up a break in the first set before finally taking it in a tiebreaker. Tsonga was broken at love to start the second set but then reeled off six straight games. “It's really good to win for the first time here,” said Tsonga, whose only previous appearance in the end-of-season tournament was in Shanghai three years ago. Defending champion Roger Federer was to face longtime rival Rafael Nadal later Tuesday at the O2 Arena. Fish followed his opening three-set loss to Nadal with a second straight defeat. The 29-year-old American ranted at the umpire during one changeover — although he later said it was a “friendly exchange” — and hit his troublesome left leg with his racket several times. The pain didn't stop him from attempting a between-the-legs shot in the tiebreaker. He also ran full speed across the court to reach a short ball toward the end of the second set before vaulting the courtside bench. Fish's chances of extending his first appearance at the tournament beyond Thursday's final Group B match against Federer are slim, especially given his physical condition. “You work so hard to get here for 10 months, 10-1/2 months,” Fish said. “I get all the way here and I couldn't do the things that I wanted to do.” Tsonga, beaten in three sets by Federer in his opening match, had a chance to serve out the first set at 5-4, but sent a drive volley into the crowd from the frame of his racket on his way to being broken for the second time. That was one of 21 unforced errors for Tsonga, but his 33 winners, including a backhand pass to take a decisive 3-1 lead in the second set, were enough to beat a fading Fish. Andy Murray's hopes of winning the Finals on home soil, however, ended Tuesday when he was forced to withdraw from the season-ending tournament with a groin injury. The 24-year-old world No. 3 had labored to a 6-4, 7-5 defeat against David Ferrer in his opening Group A match Monday, after which he revealed that he had suffered a groin strain while practicing for the prestigious eight-man tournament. Murray's chances of recovery looked bleak when he failed to keep his allotted booking on the practice court Tuesday and after chatting with his team the Scot decided to pull out of the tournament rather than risk further injury. On Monday, world No. 1 Novak Djokovic clawed his way to victory over Tomas Berdych in his opening match at the Finals. Djokovic, who arrived in London with question marks over his right shoulder, showed all the qualities that have made him the year's dominant force, digging himself out of trouble to win 3-6, 6-3, 7-6 after saving a match point deep in the decider. After losing the opening four games Djokovic gradually found his range although he still had to recover from 4-2 down in the decider before Berdych finally ran out of firepower. “That was the toughest match since the US Open,” Djokovic, who won three of the year's majors and grabbed the No. 1 ranking from Rafa Nadal, told reporters. “I wasn't very satisfied with my performance but a win is a win.”