Defending champion Naomi Osaka made a winning return to Grand Slam tennis, pulling away to beat Marie Bouzkova 6-4, 6-1 on Monday in the opening round of the US Open.

Osaka didn’t play at Wimbledon after pulling out of the French Open following the first round for mental health reasons.

It was tied at 4-all in the first set before Osaka’s power started to make its mark. The No. 3 seed won the next seven games to build a 5-0 lead in the second set. Osaka also compiled a 34-10 edge in total winners and saved all eight break points Bouzkova earned.

She won her second US Open title last year by beating Victoria Azarenka in three sets.