Summary Gilles Simon withdrew from the Open de Nice on Wednesday due to back pain.
NICE (AP) - Top-seeded Gilles Simon of France withdrew from the Open de Nice on Wednesday, casting doubts over whether he will play at the French Open.
Simon, who retired from his second-round match in Rome this month, said the pain in his upper back was "too strong."
The French Open starts on Sunday.
The 13th-ranked Simon was set to face James Duckworth of Australia for a quarterfinal spot and was replaced by French lucky loser Quentin Halys, who lost 7-6 (0), 7-6 (5).
Duckworth will be up against Borna Coric in the quarterfinals after the 53rd-ranked Croatian saved all three break points to beat qualifier Gianni Mina 7-6 (4), 6-3.
Fourth-seeded Leonardo Mayer advanced to the last-eight with a 6-4, 6-0 win over French wild-card entry Lucas Pouille to set up a meeting against Juan Monaco.
Dominic Thiem also progressed when sixth-seeded Nick Kyrgios retired with an elbow injury while trailing 4-3 in the first set.
"I expected a very tough match and I m really sorry for Nick," Thiem said. "But I have to take it like this and of course I m happy to be in the quarterfinals."
Next up for Thiem will be defending champion Ernests Gulbis of Latvia, who won his second match of the year in a 7-5, 4-6, 6-1 defeat of Alexandr Dolgopolov.
"There are still a lot of things that I need to work on," Gulbis said. "My best memories of my game were from the beginning of last year until the end of Roland Garros. Since then, I didn t have really good results and I didn t really feel well on the court because of different reasons, because of shoulder problems, because of some other reasons. Slowly it s going to change. I need to win these kinds of matches."
Also advancing was Serbia s Dusan Lajovic, who beat Pablo Carreno Busta 6-3, 4-6, 7-5 and will next take on second-seeded John Isner.
