Karolina Pliskova turned on the style to end Simona Halep's Madrid Open dominance with a 6-4 6-3 quarter-final victory on Thursday.

Halep, who thanks to Caroline Wozniacki's loss to Kiki Bertens in the previous round will retain her world number one spot, had dominated Pliskova's twin sister Kristyna a day earlier to stretch her run in the Spanish capital to 15 matches.

But Pliskova was in inspired form, making life uncomfortable for favourite Halep, who hit an uncharacteristic 26 errors.

Halep – who held a 6-1 head-to-head record over her opponent prior to the match – consequently sees her run as two-time defending champion come to an end, while Pliskova can now look forward to a last-four meeting with Petra Kvitova or Daria Kasatkina.

Halep made a swift start, breaking her opponent with a blistering forehand that Pliskova could only put into the net.

A couple of unforced errors saw Pliskova hit straight back, though, and the Czech showed great variety and neat touches en route to breaking again with a crunching forehand return.

Pliskova saw a couple of set points come and go on Halep's serve in game nine, but served out to love at the next opportunity.

Halep struggled to turn the tide in the second set and Pliskova had the break in game three when the Romanian went long with a double backhand.

Pliskova showed no signs of cracking under the pressure and a deserved triumph was sealed with a break to love, Halep going into the net to compound a miserable outing.