MELBOURNE, Australia — Novak Djokovic and Amer Delic were all smiles, hugging at the net. Outside the stadium, violence was erupting after their third-round match Friday at the Australian Open.

One of several thrown chairs left a woman briefly unconscious. Insults and water bottles filled the air. Arrests were made, with dozens of people ejected from Melbourne Park.

This was what organizers had feared when they announced before the tournament that they were instituting a no-tolerance policy for disruptions.

They wanted the focus on tennis — like Andy Roddick's 22 aces in a straight-sets victory, or top-ranked Jelena Jankovic and No. 3 Dinara Safina advancing on the women's side — not ethnic strife.

Instead of talking about how defending champion Djokovic reached the third round with a 6-2, 4-6, 6-3, 7-6 (4) victory packed with drama and good sportsmanship, the 21-year-old Serb and Bosnian-born Delic were mostly quizzed about the chaotic scene that followed — when their supporters clashed outside near a big-screen TV showing the match.

Police said about 30 Bosnian and Serbian youths were ejected from Melbourne Park. Two men were charged with riotous behavior and a third was fined on the spot. The woman who was knocked out was not seriously injured.

"There's absolutely no place for that here. This is a tennis match," said Delic, who attended the University of Illinois and lives in Jacksonville, Florida. "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."

Before finally asking reporters to change the subject, Djokovic lamented that players can't control their fans. Delic had even used his Web site to ask his backers, who were boisterous to the point of disruption in the qualifier's first two matches, to tone it down.

And that wasn't even all of the day's drama — a man was arrested after dancing across a court, naked from the waist down, as Serena and Venus Williams won a second-round doubles match.

This all was on a day when everyone was looking forward to the last match of the night, when Roger Federer was to continue his pursuit of a record-tying 14th Grand Slam against former top-ranked Marat Safin.

There was no animosity on court between Djokovic and Delic.

"Of course, I have a big respect for Amer," Djokovic said, to loud cheers from the crowd. "He absolutely deserves your applause and even more. He has one of the biggest serves on tour. It was very difficult for me to read."

The No. 127-ranked Delic got into the draw as a lucky loser from qualifying when Nicolas Kiefer withdrew with an injured ankle. Delic rallied to win two five-set matches to make the third round, his best run at a major.

Djokovic next plays the winner between American Mardy Fish and 2006 runner-up Marcos Baghdatis of Cyprus.

Roddick had a 6-3, 6-4, 6-2 win over Fabrice Santoro. The veteran Frenchman was given a bottle of champagne and a thank-you card from organizers to mark the end of his 18th Australian Open campaign.

Roddick next plays No. 21 Tommy Robredo of Spain, who beat Taiwanese player Yen-hsun Lu.

No. 8 Juan Martin del Potro of Argentina, who won a warmup tournament in New Zealand, extended his winning streak to seven matches. No. 19 Marin Cilic of Croatia ousted No. 11 David Ferrer of Spain.

On the women's side, Olympic silver medalist Safina reached the fourth round for the first time in seven trips to the Australian Open with a 6-2, 6-2 win over No. 25 Kaia Kanepi of Estonia.

Fellow Russians Vera Zvonareva, seeded seventh, and No. 10 Nadia Petrova also advanced to the fourth round.

Security was tight across Melbourne Park for the Djokovic-Delic match. In 2007, police ejected more than 150 fans one day from the same area after hostilities escalated between ethnic groups.

Extra security staff were deployed to the nearly packed stadium and kept a close eye on the most vocal fans.

There were significantly more Serbian supporters, but Delic had his share of backers, too.

When Delic broke for a 3-2 edge that was the key to taking the second set, he turned his hand toward his forehead, then pointed to his fans.

Djokovic pumped his fist and looked toward his most vocal supporters after getting the only break of the third set, when Delic whacked back-to-back double-faults to set up break point.

Several times, Djokovic applauded with his racket after great shots by Delic and gave him the thumbs-up when the American correctly challenged a line call in the tiebreaker.