World No. 7 Petra Kvitova admits that, prior to last summer, when she finally went deep in North American hard-court tournaments, her problems were not just physical, but mental.
“I think that it's both things, because if I am thinking about it too much that's for sure to show in my fitness and my game, too,” said Kvitova, who has been troubled by allergies.
The 2011 Wimbledon champion also said that at times, she has played down to the competition.
"I think that I had some matches [where I wasn't able to focus well against lower ranked players],” she said. “That's something what I need to improve and be focusing for 100 percent always.”