Dubai,
Defending champion and top seed Elina Svitolina toiled for more than two hours to reach the Dubai quarterfinals while second seed Garbine Muguruza had to wait until 2am to complete her opening victory.

Play ran exceptionally late at the event, with lengthy, slow-moving matches to blame.

Svitolina took two and a quarter hours to overcome stubborn resistance from China’s Wang Qiang 6-1 5-7 6-2.

Muguruza, the runner-up in Qatar last weekend, had to wait out a three-hour epic as Daria Kasatkina beat British seventh seed Johanna Konta 4-6 7-6(8/6) 6-2 before the Spanish second seed got on court in the early hours of Thursday.

But Muguruza at least then picked up the pace to defeat American CiCi Bellis 6-3 7-5, a match which took one and three-quarter hours and ended just before 2am.

Svitolina had to save nine of 11 break points against world number 46 Wang, who entered the field after the withdrawal of Petra Kvitova, the Qatar champion.

“I was a little bit angry at myself that I didn’t bring my best game in the end of the second set. I had to accept and bounce back,” Svitolina said.

“But I was very happy the way I was playing. In the end, the win is the win.” Konta, the first ever British woman to win a round in Dubai, was unable to get past Russian Kasatkina.

“I can only really look back on this match, and take the good things. I did do a lot of good things, (and I can) then learn from the things and try to do better,” Konta said.

Karolina Pliskova and Angelique Kerber advanced to set up a battle of ex-world number ones in the last eight.

Czech Pliskova, the third seed, beat Carla Suarez Navarro 5-7, 6-2, 6-4, while Germany’s Kerber dispatched Italian qualifier Sara Errani 6-4, 6-2.

Sixth seed Kerber, who won the Sydney title in January before reaching the Australian Open semifinals, leads the series with her Czech opponent 6-3, winning their last two matches.