Juan Martin del Potro was never off balance as the tall Argentine surged into the third round at Wimbledon on Thursday with a display of crushing power. The eighth seed, seeking a second grand slam title after his 2009 US Open success, defeated Jesse Levine 6-2, 7-6, 6-3 but with his typically big serve he also showed an athletic balance on the lush grass that caused so many problems on Wednesday. A pair of Frenchmen, Michael Llodra and Paul-Henri Mathieu, retired Thursday from Wimbledon singles matches, raising the total of players pulling out of the second round to nine, which equals the open era grand slam record for one round. Nine men and women withdrew or stopped mid-match during the first round of the 2011 US Open. All told, 12 players have pulled out of Wimbledon so far, one short of the full tournament record, set in 2008. Del Potro had no problems, employing his 210kph serve to overpower Levine, a left-hander who now represents Canada after previously playing for the US. Del Potro, who missed last month's French Open through illness, has spent most of his career shadowing the "big four" and although two of them – <a href="gopher://topicL3RoZW5hdGlvbmFsL1Blb3BsZS9TcG9ydC9UZW5uaXMgcGxheWVycy9Ob3ZhayBEam9rb3ZpYw==" inlink="topic::L3RoZW5hdGlvbmFsL1Blb3BsZS9TcG9ydC9UZW5uaXMgcGxheWVycy9Ob3ZhayBEam9rb3ZpYw==">Novak Djokovic</a> and <a href="gopher://topicL3RoZW5hdGlvbmFsL1Blb3BsZS9TcG9ydC9UZW5uaXMgcGxheWVycy9BbmR5IE11cnJheQ==" inlink="topic::L3RoZW5hdGlvbmFsL1Blb3BsZS9TcG9ydC9UZW5uaXMgcGxheWVycy9BbmR5IE11cnJheQ==">Andy Murray</a> – could still stand in his way next week he showed again that he has all the tools to break the cartel. He was only 20 when he won the US Open, over Roger Federer, but a serious wrist injury cost him nearly the whole of the following season and he has been struggling to reach the same heights since, failing to get past the quarter-finals of any grand slam. He is showing glimpses of that peak form again this week, however, as he followed up his quick-fire dismissal of Spain's Albert Ramos with another clean-striking sub-two-hour win. He said winning a medal at Wimbledon during the <a href="gopher://topicL3RoZW5hdGlvbmFsL0V2ZW50cy9VQUUgQCBPbHltcGljcyAyMDEy" inlink="topic::L3RoZW5hdGlvbmFsL0V2ZW50cy9VQUUgQCBPbHltcGljcyAyMDEy">London Games</a> has given him renewed confidence. "I've got good memories from last year at the Olympics and I enjoy playing on grass," Del Potro said, referring to a bronze-medal victory over Djokovic that should stand him in good stead, mentally, should he face the top seed in the semi-finals. Djokovic defeated Bobby Reynolds 7-6 (7-2), 6-3, 6-1 on Thursday, meaning there will be no American men in the third round for the first time since 1912. The top seed has to wait through several rain delays during the match. "With the roof closed it was a bit different, I needed some time to adjust to the conditions and it was a bit slower than I expected, but I played well in the second and third sets," Djokovic said. "I think my game is there, I just need to capitalise on my opportunities. Today I was very poor on the break points but credit to my opponent, it was a nice match and I look forward to the next one." Another man with a big serve suffered a different outcome Thursday. Milos Raonic, the No 17 seed, lost to Igor Sijsling 7-5, 6-4, 7-6 despite firing 22 aces at the Dutchman. The 21-year-old Canadian's frustrating run in slam competitions continues. It was his third second-round exit in succession at Wimbledon. His best results have been one-off fourth-round appearances on the hard courts of the Australian and US Opens. At 27, it might be too late for Tomas Berdych to aim for a new career as a front man in a rock band, but the former Wimbledon finalist would not mind trading in his racket for a mike and performing in arenas of a different kind. After reaching the third round with a straight-sets win over Daniel Brands, Berdych was asked what he would do if he were not a tennis player. The seventh-seeded Czech, a runner-up at the All England Club in 2010, said that "besides the tennis, the other best job is rock star. You're singing in front of 100,000 people". Berdych, however, declined to show off his skills when asked to perform a song. Follow us