Naomi Osaka's hopes of winning the Qatar Open ended in a straight-set quarterfinal loss to fellow former world No. 1 Karolina Pliskova on Thursday.

Osaka, a four-time Grand Slam winner returning to tennis after maternity leave, went down 7-6 (8-6), 7-6 (7-5) after saving three match points.

It was the 26-year-old Japanese star's second defeat against Pliskova this year after losing in three sets in her comeback tournament in Brisbane, Australia, last month.