Novak Djokovic, Serena Williams advance to fourth round at Wimbledon WIMBLEDON, England - While Sloane Stephens, Madison Keys and Laura Robson offered tantalizing glimpses into tennis' future, Novak Djokovic and Serena Williams reinforced their current dominance. Top-ranked Djokovic and Williams glided into the fourth round, ending a wacky week of upsets that on Saturday took out the fifth of the 10 top-seeded men. Sunday's traditional break will provide a rest day and a chance to figure out what has happened. Djokovic on Saturday became the eighth active player to win 50 tour-level grass-court matches, earning that distinction with a 6-3, 6-2, 6-2 rout of No. 28 Jeremy Chardy of France. The rangy Serb committed only three unforced errors and won 93% of his first-serve points. He will next face No. 13 Tommy Haas of Germany, who rallied for a 4-6, 6-2, 7-5, 6-4 victory over Feliciano Lopez of Spain. It was a fantastic match. I felt great from the start to the end," Djokovic said. I had that super focus and tried to be out there every point and not allow him to come back to the net and have any chance. Williams overwhelmed 42-year-old Kimiko Date-Krumm, 6-1, 6-0, in 61 minutes on Centre Court, her 600th career win. Williams and Stephens are the only American women left following Alison Riske's straight-set loss to Kaia Kanepi of Estonia. I feel like I'm pleased I'm moving well. I'm covering the court OK," said Williams, who acknowledged she was unhappy to wait to play the day's final match but simply adapted. Every time I come to Wimbledon, if I'm able to stay the second week, there's always things I'd like to improve on. Saturday's surprise was Bernard Tomic of Australia rolling past No. 12 Kei Nishikori of Japan fell to No. 23 Andreas Seppi of Italy, 3-6, 6-2, 6-7, 6-1, 6-4, and unseeded Lukasz Kubot of Poland celebrated his 6-1, 6-3, 6-4 victory over No. 25 Benoit Paire of France with some cancan kicks, entertaining the crowd on a rare sunny day. But No. 4 David Ferrer of Spain held off Alexandr Dolgopolov of Ukraine, 6-7, 7-6, 2-6, 6-1, 6-2, No. 7 Tomas Berdych of Germany beat Kevin Anderson of South Africa, 3-6, 6-3, 6-4, 7-5, and No. 8 Juan Martin Del Potro eliminated Grega Zemlja of Slovenia, 7-5, 7-6, 6-0. 14 women's seed Samantha Stosur of Australia, the 2011 U.S. Open champion, doesn't like playing on grass courts. She probably likes them less after No. 23 Sabine Lisicki unleashed a barrage of formidable serves to win, 4-6, 6-2, 6-1. That earned Lisicki a fourth-round matchup against Williams on Monday. 8 Petra Kvitova, the runner-up here last year, finished off a suspended 6-3, 2-6, 6-3 victory over Ekaterina Makarova of Russia. And No. 6 Li Na of China advanced with a 4-6, 6-0, 8-6 decision over Klara Zakopalova of the Czech Republic. A Grand Slam title is still probably beyond the reach of No. 17 Stephens, who trains in Los Angeles, but she earned her first trip to Wimbledon's fourth round. She had to wait overnight to finish her match against Petra Cetkovska of the Czech Republic after taking the first set, 7-6 (3), and losing the second set, 6-0. Their final set took more strange turns before Stephens prevailed, 6-4. "I'm excited about being in the second week again," said Stephens, who this year reached the Australian Open semifinals and the fourth round of the French Open. Puig and Stephens briefly attended the same Florida tennis academy, and Stephens recalled having faced her in a Girls 12s event, but they don't socialize. Robson, 19, thrilled the crowd by foiling Marina Erakovic's chance to serve for the match at 5-3 in the second set and pulling out a 1-6, 7-5, 6-3 victory over the New Zealander. Robson joined compatriot Andy Murray in the fourth round, the first time Britain has had two players go that far since 1998. A left-hander, Robson is inconsistent but has boundless promise. "I can definitely play better than I did today," she said. Keys, 18, showed grit in losing to No. 4 Agnieszka Radwanska of Poland, last year's Wimbledon runner-up. Radwanska covered the court well in winning, 7-5, 4-6, 6-3, crafting angled shots Keys couldn't handle. There are better days ahead for Keys, who has a booming serve and was impressive in her Wimbledon debut. "I think she's a very good upcoming player," Radwanska said. If she's going to play like this you're going to see her much often.