Juan Martin del Potro squeaked into the semifinals of the ATP World Tour Finals by beating Roger Federer, 6-2, 6-7 (5), 6-3, yesterday -- the slimmest possible margin to advance and knock Andy Murray out of the tournament.

That result means del Potro and Federer advance after a three-way tie in Group A. All three players finished the round-robin stage with two wins and identical 5-4 set records. But Murray was eliminated after winning the lowest percentage of games. Had del Potro lost one more game against Federer, Murray would have advanced at the Argentine's expense.

Murray beat Fernando Verdasco, 6-4, 6-7 (4), 7-6 (3), earlier.

Federer would have been eliminated with a straight-set loss and looked in serious trouble against the reigning U.S. Open champion. He trailed, 5-4, in the second-set tiebreaker with del Potro on serve, but the Argentine netted a simple forehand that would have set up two match points.

The deciding set then went with serve until 4-3, with del Potro needing to break to keep alive his chances of advancing. He did just that, going up, 0-40, before converting his second break point when Federer put a forehand wide. He then closed out the match with a second-serve ace.

Like in his first two matches, Federer had a poor start.

He was broken in the first game when he sent a forehand long, and then double-faulted on break point to give del Potro a 4-1 lead in the first set. Federer also showed moments of brilliance -- hitting some spectacular shots among his 28 winners -- but del Potro dictated the pace from the baseline and saved all three break points he faced.

Murray, who beat del Potro but lost to Federer in three sets, was never broken against Verdasco but struggled with an erratic serve -- mixing 18 aces with nine double-faults. He clinched the win when Verdasco missed a forehand wide on the first match point.

In Group B, Robin Soderling already has clinched a semifinal spot, while Nikolay Davydenko and Novak Djokovic are still in contention ahead of matches today. Rafael Nadal was eliminated after two consecutive losses.

Chile could be kicked out of the World Cup unless Chilean club Rangers drops a court case by Dec. 3 contesting its disputed demotion to the second division of the national soccer league. CONMEBOL, the governing body of South American soccer, said it was notified by FIFA about the possible sanction.

Rangers lost three points for using six foreign players -- the limit is five -- in a league match Nov. 8. The three points cost them relegation to the second division, and last week they appealed the case to a Chilean court.

Chile, which has not played in the World Cup since 1998, is one of five South American nations that have qualified for the 2010 tournament in South Africa. Brazil, Paraguay, Argentina and Uruguay also have qualified.

The appeal by Rangers has forced the Chilean league to suspend play in its postseason playoffs.

Rory McIlroy and Graeme McDowell shot a better-ball 58 to give Ireland a three-stroke lead over Argentina after the first round of the World Cup of Golf in Shenzhen, China. Argentina's Tano Goya and Rafael Echenique were at 11-under 61, with Japan another shot behind. The United States duo of Nick Watney and John Merrick was tied for 15th at 5-under 67 after four birdies by Watney.

England's Ian Poulter and Ross Fisher finished eight strokes back with a 6-under 66.

London Olympic organizers will avoid building a $66 million temporary arena after reaching an "agreement in principle" with two sports to move to an existing venue for the 2012 Games. The local organizing committee proposed switching badminton and rhythmic gymnastics to Wembley Arena -- adjacent to Wembley Stadium in northwest London -- rather than construct the planned facility near the Olympic Village in east London. The move was taken to save money in the wake of the global economic crisis.

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