PARIS — Denis Shapovalov's first career Grand Slam as a seeded player didn't last long.

The No. 24 seed, from Richmond Hill, Ont., lost 5-7, 7-6 (4), 7-5, 6-4 to world No. 70 Maximilian Marterer of Germany in the second round of the French Open on Thursday.

Shapovalov, 19, was coming off trips to the semifinals and round of 16, respectively, at the past two ATP Masters 1000 events on clay courts. But he couldn't duplicate those runs in his main draw debut at Roland Garros.

"I'm only 19. Not every week is going to be the semifinals of a big tournament," Shapovalov said. "It's going to be ups and downs. I just have to keep enjoying it, keep enjoying the journey."

In a battle of two players making their French Open main draw debuts, Shapovalov, 19, had more double-faults (11) than aces (six) and far more unforced errors (82) than winners (52). Shapovalov, 19, became the 10th men's seed to be eliminated at the tournament.

"I went up a set and a break (and was) feeling good and I let him back into the match a little bit," Shapovalov said. "After that, I was struggling a little bit with my serve. I could have served much better."

Shapovalov was the final Canadian player in the singles draw after Peter Polansky of Thornhill, Ont., and Vasek Pospisil of Vancouver lost first-round matches earlier this week.

"It's one of those days," Shapovalov said. "It's a little bit disappointing, but like I said credit to (Marterer). He played a really good match and he deserved to win today."

The loss prevented a possible showdown between Shapovalov and 10-time French Open champion Rafael Nadal, the top seed, in the fourth round.

Pospisil and American Ryan Harrison lost their first-round doubles match later Thursday. They dropped a 6-4, 6-3 decision to Benoit Paire of France and Federico Delbonis of Argentina.