Wimbledon: Serena Williams advances to 4th round (CBS/AP) WIMBLEDON, England - Serena Williams hit 23 aces, held every service game and barely escaped an upset bid by Zheng Jie, winning 6-7 (5), 6-2, 9-7 Saturday in the third round at Wimbledon. Williams, who erased all six break points she faced, served three times to stay in the match and held each time at love. She was pushed to deuce serving in the final game but closed out the victory with a volley winner, then hopped in glee on the Centre Court grass. The scrappy, 5-foot-4½ Zheng played with little flash but plenty of consistency, committing only 17 unforced errors. Williams rocketed a return to break for an 8-7 lead in the final set, then showed how much she wanted to win, throwing back her head and letting out a long scream. Recent French Open champions Ana Ivanovic and Francesca Schiavone also reached the fourth round at Wimbledon with victories Saturday. The 14th-seeded Ivanovic, whose only Grand Slam title came in Paris in 2008, came back from a set down to beat 22nd-seeded Julia Goerges 3-6, 6-3, 6-4. Defending champion Petra Kvitova wasn't challenged a bit, getting to the fourth round with a 6-1, 6-0 victory over 53rd-ranked Varvara Lepchenko of the United States. Playing her usual varied and attacking style, the 24th-seeded Schiavone defeated 31st-ranked Klara Zakopalova 6-0, 6-4 in 68 minutes. Schiavone won the 2010 French Open, then was the runner-up last year. The 32-year-old Schiavone reached the fourth round at Wimbledon for only the second time in 13 appearances. She was a quarterfinalist in 2009, but bowed out in the first round the following year, two weeks after becoming the first Italian woman to win a Grand Slam title. Schiavone played far steadier than Zakopalova, who finished with 20 unforced errors, 12 in the first set alone. And while Schiavone never faced a break point, she earned five on Zakopalova's serve and converted four. Ivanovic's best showing at Wimbledon was a run to the semifinals in 2007. But she lost in the third round last year, and the first round in 2010. Against Goerges, who was trying to give Germany three women in the fourth round at Wimbledon for the first time since 1987, Ivanovic kept teetering on the edge of real trouble. Serving for the match, she faced a break point at 30-40, and came up with a cross-court forehand winner that clipped the outside edge of a line. An ace set up match point, and when Goerges netted a forehand, that was it. Also on Saturday's schedule: No. 4 Andy Murray against 2006 Australian Open runner-up Marcos Baghdatis; and four American men: No. 10 Mardy Fish, No. 30 Andy Roddick, Sam Querrey and qualifier Brian Baker. The 126th-ranked Baker was the first of that quartet to play - and he won, beating Benoit Paire of France 6-4, 4-6, 6-1, 6-3 to reach the fourth round. Baker needed five operations from 2005-8, including reconstructive surgery on his right elbow, and returned to the sport about a year ago. He began 2012 ranked 458th, but Saturday's victory is expected to move him into the top 80. And featured in the day's second match on Court 12 was 100th-ranked Lukas Rosol of the Czech Republic, who hoped to follow up his remarkable second-round upset of 11-time Grand Slam champion Rafael Nadal. Rosol was facing No. 27 Philipp Kohlschreiber of Germany for a berth in the fourth round. Six-time Wimbledon champion Roger Federer gave Rosol plenty of credit for showing other players that such surprising results are possible. Almost happened to Federer, too. The owner of a record 16 major trophies, and a quarterfinalist or better at 32 consecutive major tournaments, the third-seeded Federer dropped the first two sets against 29th-seeded Julien Benneteau of France, then was two points away from losing six times, before coming all the way back Friday night to pull out a 4-6, 6-7 (3), 6-2, 7-6 (6), 6-1 victory in the third round.