Serena Williams didn't have to deal with any unexpected distractions Saturday, advancing to the fourth round at the Australian Open.
Williams, who won the title here in 2003, 2005 and 2007, started play on Rod Laver Arena on day six with a 6-1, 6-4 win over No. 41-ranked Peng Shuai of China.
The second-seeded Williams, who gave herself a "D-minus" after her last match, won the last six games of the first set without much trouble, but was broken twice early in the second.
She rallied to level at 3-3, then took a tumble when Peng wrong-footed her with a forehand cross-court winner that set up break point.
The fall seemed to wake up Williams, and she shouted "Come on!" after whacking an ace two points later and holding serve.
"It was definitely a lot better than my second round. But I'm still trying to work on some things and hoping they'll come together," she said. "I'm feeling a little rusty, for whatever reason."
The nine-time major winner's victory was routine compared with the previous day at the first major of the season.
A half-naked streaker ran onto the court during Williams' doubles victory with sister Venus.
"Well, first I saw him jump over and then I noticed he didn't have underwear on," Serena Williams said Saturday. "I thought, 'OK, I must be seeing things.'"
Also Friday, ethnic violence flared after Novak Djokovic of Serbia beat Bosnian-born American Amer Delic, leaving a woman injured, three men charged with riotous behavior, 30 people ejected by police and broken chairs scattered over the lawn area at Melbourne Park.
Serena Williams next faces No. 13 Victoria Azarenka of Belarus, who ousted 2006 Australian Open and Wimbledon champion Amelie Mauresmo 6-4, 6-2.
Azarenka, 19, won her first career title at Brisbane earlier this month and said she was growing in confidence with her winning streak.
Carla Suarez Navarro, who had an upset win over reigning Wimbledon champion Venus Williams in the second round, beat fellow Spaniard Maria Jose Martinez Sanchez 6-1, 6-4.
The 19-year-old Suarez Navarro, ranked 46th, will next play No. 21 Anabel Medina Garrigues — who beat 12th-seeded Flavia Pennetta of Italy 6-4, 6-1 — in an all-Spanish fourth-round match.
The Bondarenko sisters of Ukraine were ousted within hours of each other, missing out on a fourth-round meeting.
Kateryna lost 6-2, 6-2 to No. 22 Zheng Jie of China and older sister Alona went down 7-6 (7), 6-4 to No. 8 Svetlana Kuznetsova of Russia, who won despite making 68 unforced errors.
Kuznetsova, the 2004 U.S. Open champion, was broken when serving for the match and needed two more match points in the next game to seal it.
Two Frenchmen advanced Saturday.
Gael Monfils, a French Open semifinalist last year, had a 6-4, 6-3, 7-5 win over No. 17 Nicolas Almagro of Spain and No. 6 Gilles Simon beat No. 19 Mario Ancic of Croatia, 7-6 (2), 6-4, 6-2.
A skirmish between ethnic rivals, the streaker and an upset loss for Ana Ivanovic combined for an extraordinary Friday.
Serbian and Bosnian fans threw chairs at each other outside Rod Laver Arena following Djokovic's victory. As the players hugged at the net, the first of dozens of chairs flew on the lawn near a big-screen TV showing the match.
"There's absolutely no place for that. This is a tennis match," said Delic, who moved from Bosnia at 14 and lives in Jacksonville, Fla. "As I'm sure you all saw at the end, Novak and I are friends. We're both competitors. In the end it was a fair match, and there was no reason for such things."
Ivanovic's hopes of a return trip to the final fell apart in a 7-5, 6-7 (5), 6-2 loss to 19-year-old Alisa Kleybanova of Russia.
The fifth-ranked Ivanovic lost her serve nine times and finished with 50 unforced errors to only 23 winners.
The afternoon violence also overshadowed the night match between second-ranked Roger Federer and former No. 1 Marat Safin. The Swiss star won 6-3, 6-2, 7-6 (5).
"Terribly disappointing," Federer said of the fan conflict. "Fans, 99.9 percent of the time, are always great. Then you have some people who carry it outside of the tennis courts, lose their minds. It's unfortunate."
Victoria state police Inspector Chris Duthie said the fighting was allegedly sparked when one group threw a tennis ball at another. Security officers and police quelled the fight within minutes.
Police charged two men Friday, another on Saturday and were reviewing video to identify any other people who should face charges.
Two years ago, police ejected 150 people after similar violent clashes involving people of Balkan heritage at Melbourne Park.