Defending champion Petra Kvitova and four-time champion Serena Williams experienced contrasting fortunes during their progress to the fourth round. Williams survived a scare, coming back from a set down to complete a 6-7 (5-7) 6-2 9-7 win over China's Jie Zheng. It was far easier for Kvitova who eased through with a 6-1 6-0 victory over American Varvara Lepchenko. Ana Ivanovic, the 14th seed, beat Julia Goerges of Germany 3-6 6-3 6-4 and will meet second seed Victoria Azarenka . History made at Wimbledon . Yaroslava Shvedova became the first female player to achieve a golden set when her opponent, 10th seed Sara Errani, failed to win a point in the opening set. Australian Open champion Azarenka, last year's semi-finalist, beat Slovakia's Jana Cepelova 6-3 6-3, although she will be disappointed to have secured just five of 12 break points. There was a first at Wimbledon as Kazakh wildcard Yaroslava Shvedova made history by achieving a golden set against French Open finalist Sara Errani , who failed to win a point in the first set and eventually fell 6-0 6-4. Shvedova must now prepare to meet sixth seed Williams, who described her match against 25th seed Zheng as "tough". The American stumbled in the first-set tie-break, but romped through the second set before coming out on top in a nail-biting decider after two hours and 28 minutes on Centre Court. "I thought in the third set, if I'm going to go out I want to go out with a bang," said Williams, whose powerful serve saw her through. "I'm just fighting everything, she's playing unbelievable on grass so I'm just doing the best I can." Match stats. Williams Zheng Fastest serve First serves Unforced errors Break points Net pts Kvitova, who has lost just 13 games in three matches, hit 15 winners, her powerful play forcing her opponent into 38 errors. "I feel better every match that I'm playing here," said 22-year-old Kvitova, who has yet to drop a set in the tournament. The Czech said she would play "aggressively" against her next opponent Francesca Schiavone , who beat Klara Zakopalova 6-0 6-4. "Francesca can play very well on the grass with a good slice from the backhand. We played twice already this year on clay and hard court so we're just missing the grass, so it's time for this. "I think she can play very well, she has a good volley, so I think she will play aggressively going to the net." Austria's Tamira Paszek , who defeated former world number one Caroline Wozniacki in the first round, also progressed with a 2-6 7-6 (7-4) 7-5 win over Yanina Wickmayer of Belgium.