Andrea Petkovic is one win away from her first final in a WTA Premier Mandatory event after easing to a straight-sets victory over Karolina Pliskova in the quarter-finals of the Miami Open.

The ninth seed got off to a strong start by breaking twice in the early stages to grab a 4-1 lead.

Pliskova, of the Czech Republic, responded, though, and was level at 4-4 before failing to take three break-point chances which would have given her the chance to serve out the opener.

Petkovic took advantage of her opponent's wobble by breaking to love in the next game to claim the opener 6-4.

The second set was much simpler for the German as she didn't offer 14th-seed Pliskova a single break point, coming through 6-2 thanks to a pair of breaks.

Petkovic will face the winner of tonight's last-eight match between Carla Suarez Navarro and Venus Williams in the semis.