Defending US Open champion Naomi Osaka made a dominant return to Grand Slam tennis on Monday, defeating Marie Bouzkova 6-4, 6-1.

It’s her first Grand Slam back since pulling out of the French Open for mental health reasons. The four-time champion also did not play at Wimbledon.

After starting the first set tied at 4-all, Osaka went on a run of seven games and built a 5-0 lead in the second set. In all, the defending champion showed why she’s just that — compiling a 34-10 edge in total winners and saving all eight break points Bouzkova earned.

Following the match, Osaka took the time to make a young fan’s day by giving her a pin from the Tokyo Olympics that players were given to pass around.

“I wasn’t there for a long time so I have a couple in my bag left over,” the 23-year-old joked.

Osaka will face Olga Danilovic in the second round on Wednesday.