This means Romania's Simona Halep, the title defender, is to keep her No.1 spot in the world rankings regardless of how she finishes in Madrid.
World No.2 Wozniacki, a finalist in 2009, needed to reach the final this year to depose Halep from her place atop the Women's Tennis Association (WTA) singles rankings, but world No.20 Bertens prevented that by defeating her in just 61 minutes.
In the quarter-finals, Bertens is to face the winner of the match between Russia's Maria Sharapova and France's Kristina Mladenovic.
(This story has not been edited by Social News XYZ staff and is auto-generated from a syndicated feed.)
