Last year's Wimbledon quarter-finalist needed less than an hour to win 6-1 6-3 in her first match of the year and set up a meeting with Petra Kvitova, who has won all three of their previous contests.

There was also a strong performance from Daria Kasatkina, who defeated eighth seed Sofia Kenin 6-4 6-0 to progress.

Fourth seed Anett Kontaveit overcame Shuai Zhang 6-3 6-3 while fifth seed Paula Badosa was a straight-sets winner against 2017 French Open champion Jelena Ostapenko.

There was a surprise at the Adelaide International 2 as second seed Elina Svitolina was undone by the brutal serving of Madison Keys.

The American sent down 14 aces and won all but five points on her first serve to triumph 6-2 6-4.

Compatriot Alison Riske also progressed, beating Magda Linette 6-4 6-4, but Shelby Rogers lost to Marta Kostyuk.

Marketa Vondrousova, who had not played since losing in the Kremlin Cup semi-finals to Kontaveit in October, came from a set down to beat Viktorija Golubic.

The fifth seed battled through 5-7 6-4 6-3 in just under two and a half hours and will now face Ana Konjuh in the last 16.