Melbourne - The Australian Open was tarnished Friday by a third straight year of minor fan violence, with a woman injured and around 30 people ejected from the grounds, police reported.

Longstanding Balkan tensions which have scarred previous editions boiled over on a hot day, with rival Serbian and Bosnian fans hurling garden chairs at each other after a match won by Serbian champion Novak Djokovic over Bosnian-American Amer Delic 6-2, 4-6, 6-3, 7-6 (7-4).

Police said they turfed out around 30 people involved in scuffles, which come in the wake of a mini-riot in 2007 and a pepper-spray incident involving police in 2008.

"A number of people got into a chair-throwing contest between two groups with the result that 30-odd people were ejected from Rod Laver," said Inspector Chris Duthie of Melbourne East Police.

"We're charging two on summons and one will be receiving an on-the-spot fine. The matter was dealt with very quickly and very effectively by the police and we expect no more problems at this stage."

Witnesses said rivals began throwing chairs and punching and kicking each other. One woman was hit by the flying furniture and treated for cuts and bruises.

Fearful of potential trouble in multi-ethnic Melbourne, Delic has appealed for calm on his website as he advised fans to just come and enjoy the match.

"I'm really sad to hear about that," said the 26-year-old who moved to Florida 13 years ago. "There's absolutely no place for that here. This is a tennis match.

"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."

In another minor incident more comedic than dangerous, a male streaker wearing a T-shirt danced across the court during a doubles match featuring the Williams sisters, lasting for less than a minute before being hauled off by security officials.