Caroline Wozniacki was made to fight all the way before booking her place in the quarter-finals of her home city Sony Ericsson Open in Copenhagen. Wozniacki found herself a break down in both sets against Germany’s Angelique Kerber, who also spurned two set points in the first, before recovering to triumph 7-6 (7/4) 6-3.
Third seed Bethanie Mattek-Sands celebrated overtaking Venus Williams to become American number two by reaching the last eight with a topsy-turvy win over Johanna Larsson. After losing the first set in a one-sided tie-break, Mattek-Sands regrouped to storm through the second before having to hold her nerve to win 6-7 (1/7) 6-0 7-6 (7/5). Fourth seed Lucie Safarova beat Michaella Krajicek 6-7 (7/4) 6-4 6-2 while China’s Shuai Zhang also moved through with a 6-3 2-6 6-3 win over Galina Voskoboeva of Kazakhstan.