TORONTO — Naomi Osaka of Japan beat another top player in her return from maternity leave, routing ninth-seeded Ons Jabeur of Tunisia 6-3, 6-1 on Wednesday in the National Bank Open.

Osaka, a former No. 1 player, beat a top-20 player for the fifth time in her return.

“Everyone knows I really love hard courts. I wasn’t thinking too much. It was very instinctual,” said Osaka, a four-time Grand Slam winner. “Honestly, when I play the best players, like Ons, I tend to play better.”

Osaka will face Elise Mertens of Belgium in the second round. Mertens beat American Katie Volynets 6-3, 6-1.

Paul Badosa, a former second-ranked player making a comeback from a back injury, followed her Washington title Sunday with a 6-1, 6-4 triumph over Denmark’s Clara Tauson. The Spanish star will face fourth-seeded Jelena Ostapenko in the second round.

Third-seeded defending champion Jessica Pegula of the United States faced Karolina Pliskova of the Czech Republic in a night match.

Marina Stakusic, a 19-year-old from nearby Mississauga beat Russia’s Erika Andreeva 6-7 (5), 6-1, 6-4 in her first main-draw appearance in the event.