Australian Open champion Naomi Osaka, two-time Wimbledon champion Petra Kvitova, Madison Keys and defending champion Karolina Pliskova all reached the semifinals Friday at the Brisbane International.

Osaka beat Kiki Bertens 6-3, 3-6, 6-3, Kvitova defeated qualifier Jennifer Brady 6-4, 6-2, Keys beat Danielle Collins 6-4, 6-1 and Pliskova eliminated Alison Riske 7-6 (6), 6-3. Brady was coming off wins over Maria Sharapova in the first round and top-ranked Ash Barty in the second.

Keys, a 2017 U.S. Open finalist, reached the semifinals in Brisbane for the first time in four attempts.

"Happy to get a lot of matches in and feel like a lot of what I was working on during off-season is kind of immediately clicking," Keys said. "There's still some things that I want to do a little bit better, but it's definitely a great starting point for the year."