Australia's Bernard Tomic squandered five match points as he suffered a 4-6, 6-3, 7-6 (12/10) defeat to French third seed Jo-Wilfried Tsonga in the Marseille Open quarter-finals.
Tsonga will be playing his first semi-final of 2013 when he meets French compatriot Gilles Simon for a place in the final.
Simon beat second-seeded Argentine Juan Martin Del Potro, last weekend's Rotterdam champion, who needed treatment on a thigh injury, 6-4, 6-3 in his quarter-final.
"I felt I was playing better than him, but there were some holes in my game," said Tsonga after his match against 20-year-old Tomic, the world number 46.
"I am happy to get through because it was very, very tense."
Earlier Friday, Russian qualifier Dmitry Tursunov reached the last four with a 7-6 (9/7), 1-6, 7-5 victory over Gilles Muller, the big-serving player from Luxembourg.
Tursunov will face top-seeded Czech Tomas Berdych, who beat Polish seventh seed Jerzy Janowicz 6-3, 6-7 (0/7), 6-3, for a place in the final.