Roger Federer recovered from a set down to beat fellow Swiss Stanislas Wawrinka 2-6, 6-3, 6-2 on Friday and reach the Stockholm Open semifinals.
Wawrinka was in superb form in the first set, breaking in the first and fifth games, as Federer made some uncharacteristic errors. Wawrinka led 2-0 in the second set when Federer began to dig deep, breaking Wawrinka twice and taking the match to a third set.
The 16-time Grand Slam winner then hit his stride to win going away.
The win against his Olympic gold-winning doubles partner marks the latest milestone in Federer's glittering career. It was his 50th victory of the season, making him only the fifth player since 1968 to win that many times in nine consecutive seasons. The last was Pete Sampras.
Federer meets fourth-seeded Ivan Ljubicic of Croatia in the semifinals. Finland's Jarkko Nieminen and Germany's Florian Mayer play in the other semifinal match.
Nieminen routed American wild card James Blake 6-0, 6-2, in just 49 minutes. It was the first time that Nieminen has beaten the two-time champion in seven contests.
Mayer surprised second-seeded Robin Soderling 7-6 (8), 6-1 in front of an expectant crowd at the Royal Tennis Hall. The fifth-ranked Swede would have qualified for the ATP World Tour Finals had he won, but Soderling instead made numerous unforced errors throughout the match.
Mayer took the first set after a tense 10-8 tie-break and broke Soderling twice in the second set for the win.
''I think it's one of the best three victories in my career,'' Mayer said. ''He's top 10 in the world, I beat him at home in Stockholm, indoors on his favorite surface, so I'm very happy.''
Ljubicic came from a set down to beat stubborn countryman Ivan Dodig 4-6, 6-2, 6-4.
''I maybe was a little too defensive in the beginning,'' Ljubicic said. ''He was playing really good and then I started to be a little bit more aggressive, it worked out better.''
