"I didn't want to let anything bother me, no matter what happened," said 24-year-old Osaka, who added that "the last match I played was not the greatest memory for me".

"I wanted to prove that I could come back out here and compete, and no matter if I won or lost, to just know that I had the best attitude I could."

Osaka's win was her 50th in WTA 1000 tournaments and sets up second-round meeting with 13th seed Angelique Kerber.

In the men's draw, Australia's Nick Kyrgios sealed a comfortable first-round victory over Frenchman Adrian Mannarino.

Wildcard Kyrgios, who has slipped down the world rankings from 13th to 102, hit 12 aces and did not face a single break point in his 7-6 6-3 win.

"It was a hell of a performance," said Kyrgios, who stressed that he will be a "complete underdog" when he faces Russian fifth seed Andrey Rublev in the second round.

Britain's Jack Draper, the world number 146, is also through to round two where he will face British number one Cameron Norrie.

Draper, 20, beat Frenchman Gilles Simon 7-5 6-1 to earn his first Masters-level victory and boost his hopes of moving into the world's top 100.