Petra Kvitova, twice a Wimbledon champion, showed signs of kick-starting her year on the surface she likes most by making a timely dash into the second round of the Aegon Classic.

Kvitova, who has been troubled by illness, personal setbacks and a 10-month title drought, beat both her long-time friend Lucie Safarova and frequent downpours to advance by 6-3, 6-3 in this Wimbledon warm-up event.

The forceful left-hander timed the ball well on a slick surface which gave several players problems in adapting against an opponent who finished last year in the top ten for the first time.

The success raised the fifth-seeded Czech's hopes that her game might develop sufficiently to challenge for a third Wimbledon title, whilst evading schedule congestion.

"I love playing on grass, especially at Wimbledon, and have great memories," Kvitova said. "It's kind of my style of the game playing on this.

"Normally I have some problems with movement starting on grass, but I felt good with that as well today."

Only half an hour later Angelique Kerber, the Australian Open champion and the titleholder, contested only seven games with Peng Shuai of China before rain brought a three-and-a-half hour interruption.

Eventually Kerber was sufficiently consistent to complete 7-6(7-3) success without looking at her best against a hard-to-read opponent who hit with both hands on each side.

Another seed, Karolina Pliskova, the eighth, lost 6-4, 7-6(9-7) to Barbora Strycova, in a similarly rain-interrupted contest. The result was not entirely surprising for Pliskova seemed jaded after five matches last week while winning the Nottingham title, and Strycova is a former finalist here.

Less lucky were Agnieszka Radwanska, the top seed, who played only eight games with CoCo Vanderwegh, and Belinda Bencic, the fourth seed, Carla Suarez Navarro, the fifth seed, and Caroline Wozniacki, the former world number one, all of whom failed to get on court.