Wozniacki battles through

Caroline Wozniacki recovered from a set down to defeat Karin Knapp and reach the quarter-finals at the Istanbul Cup.

The top seed, who is chasing her first title of the season, had not dropped a game in her opening win over Belinda Bencic but found Knapp a tougher prospect.

However, after the Italian won the first set, Wozniacki turned things round impressively to secure a 4-6 6-2 6-1 victory.

Third seed Klara Koukalova did not fare so well, the Czech beaten 6-1 6-3 by France's Kristina Mladenovic, who next meets former French Open champion Francesca Schiavone, a 6-1 6-4 winner over seventh seed Bojana Jovanovski.

Fourth seed Elina Svitolina had no problem booking her spot in the last eight, the Ukrainian winning 6-0 6-3 against Stefanie Voegele.