METZ, France (AP) Top-seeded Stan Wawrinka withdrew from the Open de Moselle with an ankle injury on Friday while former two-time champion Gilles Simon made it to the semifinals.
The French Open champion was scheduled to face Philipp Kohlschreiber in the quarterfinals at the indoor hard-court tournament but was unable to play.
Wawrinka, who has already qualified for the ATP World Tour Finals from Nov. 15-22 in London, hurt his right ankle during his 4-6, 6-3, 7-6 (4) win over Dustin Brown in the second round.
''Unfortunately I have to pull out because yesterday I twisted my ankle at 5-4 in the first set,'' said Wawrinka. ''It was painful in the match, but still OK with tape on it. But after a lot of treatment last night and some tests this morning, it's dangerous for me to play because the pain is still there. So I will have to see a doctor to see if I will be OK in the next few weeks.''
The second-seeded Simon, who clinched his titles in the northeastern city in 2010 and 2013, converted two of his five breakpoints and withstood 12 aces to advance past Gilles Muller 6-4, 6-4. Next up for Simon is sixth-seeded Martin Klizan, who rallied to beat fourth-seeded Guillermo Garcia-Lopez 4-6, 6-3, 7-6 (4).
In the semifinals, Kohlschreiber will be up against third-seeded Jo-Wilfried Tsonga, who came back from one set down to beat fellow Frenchman Nicolas Mahut 6-7 (6), 6-3, 7-5.