The former SW19 champion made her comeback at the French Open in May after six months out of the game.
WTA Staff

BIRMINGHAM, England - Petra Kvitova says a great serve is essential to success on grass as she continues her return to the game.

The 27-year-old has reached the quarterfinals of the Aegon Classic in Birmingham this week, her second tournament since returning from a knife attack in her home late last year.

As a seventh-seed wildcard she has made the last eight following straight-set victories over Tereza Smitkova and Briton Naomi Broady.

"It is important to have a great serve, a lofted serve, on the grass," she told after beating Broady on Wednesday. 

"It is always very helpful. I hadn't won a game and was really struggling. It is always about the ups and downs during the match and most of the time the serve helped me a lot."

The Czech made a comeback from her enforced break at the French Open in May, where she beat Julia Boserup in an emotional match.

"I'm comfortable on the grass," she continued, looking forward to next month's Wimbledon Championships. "I was looking forward to this part of the season. It's here and I am enjoying every moment out there.

"I thought [Broady] was going to be a dangerous player on the grass. I expected a tough match and it was. It was about the first break in the set and I was a little bit 'upper' than her and she didn't serve that well afterwards."

Kvitova's return to the All England club returns her to the scene of her singles triumphs in 2011 and 2014, and she hopes to continue her preparations by maintaining her run in Birmingham this week. 

She awaits either Zhang Shuai or Kristina Mladenovic, the French fifth seed, in the last eight.