Kei Nishikori reached another milestone on Sunday, becoming the first Japanese man in more than 80 years to advance to the quarterfinals at the French Open.The fifth-seeded Nishikori, who has yet to drop a set at this year’s tournament, progressed to the last eight at the clay-court Grand Slam for the first time with a 6-3, 6-4, 6-2 victory of Teymuraz Gabashvili of Russia on Sunday.