World number one Halep is playing in only her third tournament of 2018 and that may explain her rustiness early on, Pliskova able to break in the Romanian's first two service games.

It was an opportunity Pliskova was unable to take advantage of, though, as Australian Open runner-up Halep eventually found her groove – the foot problem that troubled her in Doha not causing any issues.

From 3-1 down she won five of the next six games to take the first set, although she still only managed seven winners to Pliskova's 14.

With the wind in her sails Halep turned the screw, her trademark fist pump becoming a regular sight to the crowds in California as her powerful groundstrokes began to appear.

A crushing backhand secured a double break early in the second, and there was nothing Pliskova could do to stop the top seed.

Even a sloppy service game midway through the second set could not fluster Halep, recovering immediately to restore her advantage with an array of pinpoint shots from the baseline.

Two simple service games followed to secure her progress, and end any doubts that she could be hampered in the coming days.