Naomi Osaka knocked out of French Open after first-round defeat against Amanda Anisimova

Four-time grand slam champion Naomi Osaka exited the French Open in the first round on Monday as she lost 7-5 6-4 against Amanda Anisimova.

The 20-year-old Anisimova, a surprise semifinalist at Roland Garros three years ago, has now beaten Osaka in back-to-back grand slams after her third-round victory at the Australian Open in January.

In their latest clash at Roland Garros -- arguably the pick of the first-round matches in the women's draw -- a close, seesawing first set featured five breaks of serve, including the first three games of the match.