PETRA Kvitova was unsure of her form coming into the Championships after illness forced her to miss a few days' practice, but she has looked in formidable shape in the two matches she has played so far.

The defending champion dropped only one game in her first-round match on Day Two, and on Day Four she fared almost as well, beating Kurumi Nara of Japan 6-2, 6-0 in under an hour.

Tougher challenges await - next up on Saturday is the former world No 1 Jelena Jankovic, who beat Evgeniya Rodina 6-7, 6-1, 6-3 - but it is so far so good for the Czech. "I'm very pleased how everything is going so far," she said.

"I can't really say surprised. I think I'm kind of handling it better than 2012 when I was defending my first title. I still have a lot of space where I can improve for the next match - that's a good sign."

Kvitova has never played Jankovic, the No 28 seed, on grass, but is sure she will be in a more demanding contest. "It's always a big challenge to face her," she added about her Serbian opponent, who won the mixed doubles here with Jamie Murray eight years ago.

"It's always a little bit special. Always she has sort of weapon to play - specially her backhand, it's really great. But I'm going to try the best playing the same way as I normally play."

The biggest casualty on Day Four was the No 8 seed, Ekaterina Makarova of Russia, who lost 2-6, 5-7 to Slovakia's Magdalena Rybarikova, losing 2-6, 5-7. Alize Cornet, seeded 25th, also fell at the second hurdle, going down in three sets by Olga Govortsova.

The other leading seeds in action enjoyed better fortunes. Caroline Wozniacki - like Jankovic a former world No 1 who is enjoying a comeback after some tough times - beat Denisa Allertova in straight sets. Wozniacki, seeded five, beat Denisa Allertova in straight sets, and now meets Camilla Giorgi, the No 31 seed, who beat Lara Arruabarrena, also in two.

Sabine Lisicki, the No 18 seed who was beaten by Marion Bartoli in a one-sided final two years ago, battled past Christina McHale in three sets. On her best form the German is a match for nearly anybody, but there is still a major question about her ability to handle the big occasion mentally. If she gets that side of her game right, however, she should be able to get past Wozniacki in the quarter-final before most likely coming up against Kvitova in the semi next Thursday.

Angelique Kerber, the No 10 seed, won in two against Anastasia Pavlyuchenkova. Other seeds to go through included Madison Keys, the No 21, and Agnieszka Radwanska, the No 13.