Rafael Nadal lost to qualifier Martin Klizan 6-7 (7), 6-4, 6-3 Friday in the quarterfinals of the China Open.
The No. 2 seed struggled in just the third match he has played since his more than two-month hiatus due to a right wrist injury. The loss was Nadal's first to a qualifier in 10 years.
Earlier this year, Klizan defeated U.S. Open finalist Kei Nishikori at the French Open.
After Nadal's victory over German qualifier Peter Gojowczyk on Thursday to reach the quarterfinal, Nadal complained about the ball used in the tournament.
From The New York Times:
"The ball is so bad here," Nadal said. "If you throw the ball on the floor, the bounce goes everywhere. Is not a question of winning or losing. I won in Rio (earlier this year) with this ball.
"It's just that we're competing at the top level of our sport, tennis, and the ball is an important thing."
Elsewhere on the men's bracket, No. 1 seeded Novak Djokovic beat Grigor Dimitrov 6-2, 6-4, and No. 6 seed Andy Murray beat U.S. Open champion Marin Cilic 6-1, 6-4.
Murray and Djokovic will play in the semi-finals of the tournament.