Melbourne  - Balkan passions played out on court while fans remained restrained as Serb Novak Djokovic posted a 6-2, 4-6, 6-3, 7-6 (7-4) win Friday over Bosnian-American Amer Delic to advance at the Australian Open.

While police reported that a handful of unidentified troublemakers were turfed out the gates of Melbourne Park for scuffles and chair throwing in the beer garden park, the atmosphere for the heated third-round match could only be classified as a low simmer.

"The crowd enjoyed it, the fans were all right," said holder Djokovic, defending the first major title of his career. "There were some points when they started cheering between the serves or during the point.

"But that was very rare. I was very happy with the way the Serbs and Bosnians were cheering, reacting on everything."

Djokovic, seeded third, saved a pair of set points in the tenth game of the fourth set which would have allowed lucky loser Delic to take the contest into a deciding fifth.

Delic played well over his ranking of 127, hammering 16 aces in a contest stretching past the three-hour mark.

Djokovic trailed on winners, with 30 to the 46 of an inspired opponent playing in a Grand Slam third round for the first time.

Djokovic is knocking on the number two ranking held by Roger Federer, who faced a showdown in the evening at Melbourne Park against 2005 champion Marat Safin.

Djokovic has been ranked third for all but one week since July, 2007, but has been within one victory of claiming number two on three occasions (2008 Hamburg, 2008 Roland Garros and Sydney last week).

"I need some matches like this to feel what the Grand Slam is all about," said the winner. "It's about those long four, five set matches in the heat.

"I didn't really plan to be that long on the court, of course. You always want to finish the job as soon as possible."

Argentine eighth seed Juan Del Potro recovered from a slow start to put out Gilles Muller of Luxembourg 6-7 (5-7), 7-5, 6-3, 7-5.

Rising Croatian Marin Cilic, Croatia crushed Spaniard David Ferrer, the 11th seed, 7-6 (7-5), 6-3, 6-4 to line up against Del Potro in the next round.

"Obviously he's playing good," said Cilic, who has recently broken into the Top 20. "He won in Auckland and is coming in good form, good shape. He's playing very well.

"He will be a tough opponent to beat."

Women's top seed Jelena Jankovic was untroubled in a 6-4, 6-4 sweep of Japan's Ai Sugiyama to advance into the weekend.

Number three third seed Dinara Safina stayed on course for a shot at the number one ranking, gaining a victory for the Safin family hours before her brother Marat was to face Roger Federer.

Safina, the losing finalist at the French Open, reached the fourth round in Melbourne for the first time in her career, posting a 6-2 6-2 win over Kaia Kanepi.

Safina is one of three women chasing Jankovic, with a title next Sunday enough to assure the 22-year-old of the breakthrough top spot.

Russian Vera Zvonareva, seeded seventh, beat Italian Sara Errani 6-4, 6-1 while Russian number 10 Nadia Petrova, advanced without a fight as opponent Galina Voskoboeva quit with a back injury after losing the first set 6-1.

Safina faces off at the weekend against French 15th seed Alize Cornet, who defeated Daniela Hantuchova 4-6, 6-4, 6-2. (dpa)