Dudi Sela retired in the second set of his first round match in the Cincinnati Open on Monday after aggravating a nagging groin injury. The 24-year-old, who remained at number 34 in the world rankings on Monday, was trailing Spain's Nicolas Almagro 6-4, 1-0 when he decided not to risk his health any further just two weeks before the start of the US Open in New York. Sela has also decided to pull-out of next week's tournament in New Haven to make sure he will be fit for the year's final Grand Slam and Israel's Davis Cup semifinal against Spain next month. Meanwhile, Andy Murray has overtaken Rafael Nadal in the ATP rankings, becoming the first British man to reach No. 2. Roger Federer is still No. 1 in Monday's rankings. Murray's Rogers Cup title in Montreal on Sunday moved him up to No. 2 for the first time, while Nadal is now No. 3 after being ranked No. 1 from August 2008 through June 2009. The only other change in the top 10 this week is Fernando Verdasco's rise from No. 11 to No. 10, supplanting Fernando Gonzalez. Dinara Safina remains No. 1 in the WTA rankings, followed by No. 2 Serena Williams and No. 3 Venus Williams. Murray took the court to face Juan Martin Del Potro on Sunday knowing no matter what the result of the Rogers Cup final, he would be soon be ranked No. 2 in the world. Not satisfied having reached that goal, Murray withstood his toughest test of the tournament and defeated Juan Martin Del Potro 6-7 (4), 7-6 (3), 6-1. "I love winning tournaments, it's great, and every player will tell you the same thing," Murray said. "But it's tough because I've never been to No. 2 in the world before, so that's new to me. I've won a couple of Masters Series [events] now, and it still feels great. But getting to No. 2, maybe because it's something different it means a little bit more." The 22-year-old from Scotland was assured before the final of leapfrogging Nadal into the second spot. The victory gave Murray an additional 400 ranking points to get him to 9,250 compared to 11,040 for world No. 1 Federer and 8,665 for Nadal. The third-seeded Murray matched his career best from last season with his fifth tournament win of the year and improved his record to 11-4 against top-10 players this season. AP contributed to this report.