Caroline Wozniacki battles back to defeat Petra Kvitova

Caroline Wozniacki has fought her way back from a set down against Petra Kvitova to seal her place in the quarter-finals of the Cincinnati Open.

The Dane was twice broken as she lost the first set 6-3, but the Czech seventh seed could not maintain that momentum.

Wozniacki put immense pressure on Kvitova's serve, breaking five times on her way to taking the next two sets 6-2 6-3.

The 23-year-old will face Victoria Azarenka - 6-3 6-4 winner over Magdalena Rybarikova - for a place in the last four.