Angelique Kerber has got revenge on Naomi Osaka after beating her in the first round of the Pan Pacific Open on Monday.

The former world number one became only the second women's defending champion to lose in the US Open first round when she was beaten by Japanese teenager Osaka 6-3 6-1 less than a month ago, but she got her own back in Tokyo, sealing a relatively routine 6-3 6-4 success.

The two-time Grand Slam winner, who has not won a WTA title in over a year, was understandably delighted to beat Osaka, particularly as the 19-year-old reached the final of the event 12 months ago.

"It's always tough to play against her," Kerber told the WTA website after her victory. "I was trying to come out here and really focus on every single point and make it better than last time... she's a great player, great, talented player and tough opponent."

Kerber's reward for reaching round two is a clash with either American qualifier Madison Brengle or Russia's Daria Kasatkina, with those two players set to go head-to-head in their first-round clash during the early hours of Tuesday morning UK time.

Second seed Karolina Pliskova and British number one Johanna Konta are also in Kerber's side of the draw, so the 29-year-old faces a tough battle if she wants to go all the way in the tournament.