'Serena always finds good form for the important points'

Petra Kvitova is not the type to talk herself up even if she does arrive at Wimbledon as the defending champion.

Instead the powerful Czech second seed said world number one Serena Williams has a great chance to complete a calendar year grand slam this year, having already bagged the Australian Open and French Open titles.

"I think that Serena has really great chances to do it. I think she is really a big champion. She's always trying to find a good form for the important points.

"We'll see. I think that she's really in the good way."

No other player apart from Serena or sister Venus, who also has five Wimbledon titles, has retained the Wimbledon crown in the last 19 years, but Kvitova appears stronger mentally than when she stormed through the pack to win in 2011.

Ranked second in the world she beat Serena in Madrid this year on her way to the title having taken a break earlier in the season, missing the Indian Wells and Miami tournaments to re-charge her batteries for the slams.

"I think a lot of athletes want to have a break, but they didn't do it," Kvitova told reporters.

"But anyway, I mean, I feel much better than before. I'm really happy to be back on the court to play tennis, to really do what I love. That's the important thing.

"I think it was a really tough decision for me to miss the two big tournaments during March. I'm glad that I did it."

Kvitova faces big-hitting Kiki Bertens of the Netherlands in the first round on Tuesday, when she hopes to have shaken off a cold that forced her to pull out of the Eastbourne championships last week.

"I hope on Tuesday I will be ready 100 percent, but of course, I missed a few days practice. But that's how it is," she said.