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.
In the late match, third-seeded defending champion Jessica Pegula of the United States topped Karolina Pliskova of the Czech Republic 7-5, 6-4 in the second round.
In another night match, 15th-seeded Leylah Fernandez of Canada beat Nao Hibino of Japan 6-3, 5-7, 6-1.
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.