Sloane Stephens beaten in Acapulco but Daria Gavrilova advances

Top Seed Sloane Stephens has been knocked out the Mexico Open by world number 138 Stefanie Voegele.

The US Open champion appeared sluggish against Switzerland’s Voegele, who claimed her biggest win in five years with a 6-4 5-7 6-2 success.

Voegele will now face qualifier Rebecca Peterson, who beat fourth seed Zhang Shuai 6-2 6-1 to advance to the semi-final.

Elsewhere, number three seed Daria Gavrilova had no real problems, beating Veronica Cepede Royg 6-4 4-6 6-2, while defending champion Lesia Tsurenko overcame number two seed Kristina Mladenovic in straight sets.