Daniil Medvedev still can't find a way to beat Gilles Simon, losing 6-4, 6-0 in the Open 13 quarterfinals on Friday for a third loss in three matches against the French veteran.
The US Open runner-up and top seed in Marseille dropped his serve five times against the 35-year-old Simon, after breaking him in the first game.
Defending champion Stefanos Tsitsipas reached the semifinals by beating Vasek Pospisil 7-5, 6-3 in their first meeting. The second-seeded Tsitsipas did not face a break point and broke his Canadian opponent's serve three times.
The big-hitting Greek next plays Alexander Bublik, who secured a career highlight upset win over fourth-seeded Canadian Denis Shapovalov 7-5, 4-6, 6-3.
The Kazakh player, trailing 4-4, 0-40 in the first set, reached only his third semifinal at this level. He lost both of his career finals last year.
It was the first time three Canadians reached the last eight of an ATP Tour event since 1990.
But the seventh-seeded Felix Auger-Aliassime, who saved match points in his two previous matches, was the only one to advance.
He beat qualifier Egor Gerasimov of Belarus 7-5, 6-2 and next faces Simon, who had a career-high ranking of sixth in 2009 and has 14 titles.