LONDON - Four-time champion Serena Williams clinched a marathon triumph over China's Zheng Jie to reach the Wimbledon last 16 on Saturday as Lukas Rosol, the conqueror of Rafael Nadal, returned to anonymity.
Sixth-seed Williams, playing in her 13th Wimbledon, saw off 25th-seed Zheng, 6-7 (5/7), 6-2, 9-7 and will tackle Yaroslava Shvedova of Kazakhstan for a place in the quarter-finals.
"It was good to win. I needed a tough match and she's always playing me incredibly well," said Williams, who unleashed a Wimbledon record 23 aces.
Wildcard Shvedova will go into Monday's fourth round tie having made history as the first woman at a Grand Slam to achieve a Golden Set. She won all 24 points in a first set 6-0 wipeout of Italian 10th seed, and French Open runner-up, Sara Errani on her way to the last 16 for the first time.
Shvedova took the second set 6-4.
"Today I laid a golden egg," the Kazakh later tweeted.
Czech world 100 Rosol had caused one of the greatest upsets in the history of the sport when he beat world number two Nadal in five sets in the second round under the Centre Court roof on Thursday.
But on a windswept Court 12 on Saturday, normal service was resumed as German 27th seed Philipp Kohlschreiber, who beat Nadal on grass at Halle two weeks ago, eased to a 6-2, 6-3, 7-6 (8/6) win and a first appearance in the last 16.
Kohlschreiber will tackle American qualifier Brian Baker for a place in the quarter-finals.
"It was a little bit windy and that didn't help me a lot. He was playing pretty good, he didn't gave me a lot of chances," said Rosol, who will come back down to earth with a bump next week when he plays a second-tier Challenger in Germany.
Meanwhile, Baker's fairytale return hit a new high when he enjoyed a 6-4, 4-6, 6-1, 6-3 victory over France's Benoit Paire.
Baker lost six years of his career to an assortment of injuries that left him needing five different operations on a hernia, left and right hips and right elbow.
The 27-year-old, who started the year ranked 458, will rise to at least 78 after his performances at Wimbledon.
"It's been unreal," said Baker, who took a job as a college tennis coach to maintain his feel for the sport during his lengthy lay-off.
Argentine ninth seed Juan Martin Del Potro defeated Kei Nishikori, the first Japanese man since 1995 to reach the third round, 6-3, 7-6 (7/3), 6-1 and will face either three-time runner-up Andy Roddick or Spain's David Ferrer.
American 10th seed Mardy Fish, a quarter-finalist last year and playing his first tournament since undergoing a heart operation, beat Belgian wildcard David Goffin 6-3, 7-6 (8/6), 7-6 (8/6).
Fish will face either French fifth seed Jo-Wilfried Tsonga or Slovakia's Lukas Lacko.
Later Saturday, British fourth seed Andy Murray takes on Marcos Baghdatis of Cyprus with the winner to meet either Croatia's Marin Cilic or Sam Querrey of the United States.
Defending women's champion Petra Kvitova wasted little time moving into fourth round as the Czech took just 53 minutes to crush America's Varvara Lepchenko 6-1, 6-0.
Kvitova, seeded fourth, will play former French Open champion Francesca Schiavone for a place in the quarter-finals.
Former world number one Ana Ivanovic, the 14th seed, reached the last 16, coming from behind to clinch a 3-6, 6-3, 6-4 win against Germany's Julia Goerges.
Ivanovic will play second seed Victoria Azarenka, a semi-finalist in 2011, who put out Slovak qualifier, and world number 178, Jana Cepelova, 6-3, 6-3.
Also going through was Austria's Tamira Paszek, the first round conqueror of former number one Caroline Wozniacki.
Paszek enjoyed a 2-6, 7-6 (7/4), 7-5 win over Belgium's Yanina Wickmayer and will face Italian 21st seed Roberta Vinci who defeated Croatia qualifier Mirjana Lucic in two tie-break sets.