He defeated Teymuraz Gabashvili in three straight sets 6-3 6-4 6-2. He’ll meet Jo-Wilfried Tsonga in the semi-finals on Friday.
Nishikori is the first Japanese man in 82 years to advance so far in the French Open, according to SkySports.
He has been playing under the tutelage of tennis great Michael Chang who won the French Open in 1989.
Last year he played in the finals in the U.S. Open, becoming the first Japanese man to make it to a Grand Slam final. He lost to Marin Čilić.