Caroline Wozniacki saw her chances of reclaiming the world number one spot disappear as an inspired Kiki Bertens coasted into the quarter-finals of the Madrid Open on Wednesday.

Australian Open champion Wozniacki could have returned to the top of the WTA rankings by outperforming Simona Halep this week, but was outclassed by Bertens in a 6-2 6-2 defeat.

Bertens, who has won all five of her WTA titles on clay courts – including at Charleston last month – was rewarded for taking the game to the world number two, who succumbed to defeat in just 61 minutes.

The Dutchwoman's reward is a last-eight meeting with either Kristina Mladenovic or Maria Sharapova.

Bertens was brilliant from the off, breaking in the first game thanks to an exquisite drop shot that was quickly followed with a punishing forehand.

Wozniacki hit back immediately, but was on the back foot again in game three - Bertens converting the third of three break points when her opponent put a simple-looking double backhand into the net.

A third break duly arrived, which left Wozniacki with too much to do to save the opener, and she dropped serve again immediately in the second, going long with a forehand.

Even when facing three break points in game four, Bertens refused to blink and she fought back to hold before another long forehand from Wozniacki gifted Bertens a break to love and a 5-2 second-set lead.

And another simple hold put paid to Wozniacki's chances of returning to the summit of the women's game.