Madison Keys beat Samantha Stosur 7-5, 6-3 on Wednesday to be among three Americans with second-round wins at the Brisbane International.

Stosur had beaten former world No.1 Angelique Kerber to progress beyond the first round at the tournament for just the second time in seven years on Monday.

The Australian had an early break against Keys, the 2017 U.S. Open finalist, but the American broke back in the next game and then in the 12th game to take the first set.

Keys broke serve again to begin the second set before sealing victory in 77 minutes.

"Sam obviously has a great serve and a great forehand and she's really tricky off of her slice," Keys said. "So I've known that in the past; I just felt like in the past I wasn't doing a great job at handling my side of the court."

Stosur will continue her Australian Open preparation at the Hobart International next week.

In earlier American victories, Alison Riske beat Barbora Strycova 6-3, 6-4 and Danielle Collins defeated Yulia Putintseva 6-1, 6-0.

Australian world No. 1 Ashleigh Barty won't begin her singles campaign until Thursday but is already just one win from the doubles final.

Barty combined with Dutch player Kiki Bertens to beat second-seeded Nicole Melichar and Yifan Xu 6-3, 6-2 in less than an hour on Wednesday.

Barty will play American Jennifer Brady in the second round in singles on Thursday.