Former champion Petra Kvitova needed all her considerable experience to beat Latvian Jelena Ostapenko 6-2 5-7 6-1 and reach the quarter-finals of the Qatar Open on a windy Wednesday in Doha. The Czech number eight seed, who won the Qatar title in 2018, looked on course for a routine victory after running away with the first set, but former French Open champion Ostapenko clawed her way back into the contest with some gutsy hitting from behind the baseline. The 22-year-old, who rivals twice-Wimbledon champion Kvitova in terms of sheer power, improved her first serve percentage from 52% to 73% in the second set and converted four of her six break point chances to level the match. Both players struggled for control in the swirling wind that ripped through centre court, but it was the 29-year-old Kvitova who kept her head as Ostapenko faded badly in the decider. "There's no chance to have tactics in this wind," Kvitova said in an on-court interview. "It's difficult to put the serve in and she returned the second serve well. I needed to be more patient. It was about taking time and it was really difficult." Kvitova served nine aces but made an equal number of double faults, while Ostapenko also struggled in the conditions, with 11 double faults of her own. The Latvian also made a typically high 32 unforced errors, and hit 11 fewer winners than Kvitova, which sealed her fate. Top seed Ashleigh Barty advanced to the quarters via a walkover after her opponent Elena Rybakina withdrew with a strain in her leg. Barty will face the winner of the match between Spanish 11th seed Garbine Muguruza and unseeded Ukrainian Dayana Yastremska, which will take place later on Wednesday. Russia's Svetlana Kuznetsova also advanced via a walkover after her American opponent Amanda Anisimova withdrew due to illness. Kuznetsova will next face Swiss world number nine Belinda Bencic, the fourth seed, who beat Kazakhstan's Yulia Putintseva 6-4 6-3 earlier in the day.