MELBOURNE, Jan 23: Violent clashes between ethnic factions again marred the Australian Open tennis on Friday but the ugly stain on the first Grand Slam of the year was almost washed away by a heart-warming victory for Jelena Dokic.

Yugoslav-born on-again-off-again Australian Dokic put years of personal heartache behind her to oust 11th seed Caroline Wozniacki just hours after ethnic Serbs and Bosnians had hurled chairs at each other and exchanged kicks and punches in riotous scenes.

That fighting had followed Serb champion Novak Djokovic’s 6-2, 4-6, 6-3, 7-6 victory over Bosnian-born Amer Delic to reach the last 16.

Groups of rival fans threw chairs at each other in the beer garden outside centre court when simmering tension boiled over under the hot Melbourne sun.

One woman was knocked cold when a chair struck her head.

Police arrested two men and ejected another 30 people from the grounds after the rival supporters traded punches and kicks.

The fight spilled outside the stadium before police got it under control.

“We have a very effective police presence here. You can’t stop everything happening but we will make sure this sort of thing doesn’t happen [again],” police inspector Chris Duthie told reporters.

Tensions between rival ethnic factions from the former Yugoslavia have become an unfortunate feature at the season’s opening Grand Slam – once dubbed the Happy Slam.

Two years ago 150 fans were ejected after violent brawling at the tournament.

The tension had been rising all week, reflected in minor incidents of rowdiness at matches and Delic had appealed on his website for calm, but to no avail.

“There’s absolutely no place for that here,” Delic said. “This is a tennis match. As I’m sure you all saw at the end, Novak and I are friends.

“We’re both competitors, obviously. In the end it was a fair match, and there was no reason for such things,” he said.

“There’s only so much we can say. You can’t stop and control everybody. Somebody gets drunk, you know, they want to cause trouble. It happens.”

The violence had overshadowed action at Melbourne Park before Dokic took to centre court under floodlights.

The 25-year-old’s personal problems and public split from her domineering father Damir were well-known to the crowd and it took her to its heart as she returned to the Open for the first time since 2006.

“I have had a tough couple of years so I am just starting from scratch now, really,” the 187th-ranked wildcard said after her 3-6, 6-1, 6-2 win. “The crowd really has been something else, really lifted me up.”

Dokic next faces Russia’s Alisa Kleybanova, who produced a gutsy performance to upset 2008 runner-up Ana Ivanovic 7-5, 6-7, 6-2.

“It was definitely the best match in my career so far,” Kleybanova beamed. “I’m so happy that I pulled through, because it was not just a win, but I really felt that I played almost my best tennis today.”

Roger Federer stayed on track for a record-equalling 14th grand slam title when he swatted aside former champion Marat Safin.

The anticipated clash of tennis juggernauts failed to materialise, though, as the Swiss totally dominated the match between former world number ones to win 6-3, 6-2, 7-6 under floodlights.

Marat’s sister, world No 3 Dinara Safina, hit her way into the last 16, however. Her 6-2, 6-2 win over Kaia Kanepi was a triumph of force over finesse. She plays Alize Cornet next after the Frenchwoman beat Slovakia’s Daniela Hantuchova.

The 10th-seeded Nadia Petrova sauntered through in double-quick time when injured Galina Voskoboeva quit after losing the first set 6-1. She plays compatriot Vera Zvonareva next.

Top seed Jelena Jankovic advanced to the fourth round after overcoming Japan’s Ai Sugiyama 6-4, 6-4 in a baseline tussle.

The Serbian will next play France’s Marion Bartoli, who beat the Czech Republic’s Lucie Safarova in three sets.

In the men’s draw, seventh seed Andy Roddick beat Frenchman Fabrice Santoro 6-3, 6-4, 6-2 and 11th seed David Ferrer lost to Croatia’s Marin Cilic 7-6, 6-3, 6-4.

Friday’s results (prefix number denotes seeding):

Men’s singles:

Third round: Marcos Baghdatis (Cyprus) bt 23-Mardy Fish (US) 6-2, 6-4, 6-4; 2-Roger Federer (Switzerland) bt 26-Marat Safin (Russia) 6-3, 6-2, 7-6 (7-5); 20-Tomas Berdych (Czech Republic) bt 15-Stanislas Wawrinka (Switzerland) 4-6, 6-1, 6-3, 6-4; 7-Andy Roddick (US) bt Fabrice Santoro (France) 6-3, 6-4, 6-2; 21-Tommy Robredo (Spain) bt Lu Yen-hsun (Taiwan) 6-1, 6-3, 6-2; 3-Novak Djokovic (Serbia) bt Amer Delic (US) 6-2, 4-6, 6-3, 7-6 (7-4); 8-Juan Martin del Potro (Argentina) bt Gilles Muller (Luxembourg) 6-7 (5-7), 7-5, 6-3, 7-5; 19-Marin Cilic (Croatia) bt 11-David Ferrer (Spain) 7-6 (7-5), 6-3, 6-4.

Women’s singles:

Third round: 29-Alisa Kleybanova (Russia) bt 5-Ana Ivanovic (Serbia) 7-5, 6-7 (5-7), 6-2; Jelena Dokic (Australia) bt 11-Caroline Wozniacki (Denmark) 3-6, 6-1, 6-2; 1-Jelena Jankovic (Serbia) bt 26-Ai Sugiyama (Japan) 6-4, 6-4; 15-Alize Cornet (France) bt 19-Daniela Hantuchova (Slovakia) 4-6, 6-4, 6-2; 16-Marion Bartoli (France) bt Lucie Safarova (Czech Republic) 3-6, 6-2, 6-1; 7-Vera Zvonareva (Russia) bt Sara Errani (Italy) 6-4, 6-1; 3-Dinara Safina (Russia) bt 25-Kaia Kanepi (Estonia) 6-2, 6-2; 10-Nadia Petrova (Russia) bt Galina Voskoboeva (Kazakhstan) 6-1 – Voskoboeva retired.—Reuters