The Australian Open draw has opened up a potential can of worms for security organisers at Melbourne Park, with rival Serb and Croatian supporters to be thrown into close proximity for Novak Djokovic's second round match against Croatia's Ivan Dodig.
Tensions between Serb, Croat and Bosnian fans at the year's first grand slam have spilled into violence in recent years, with police forced to eject dozens for taking part in mass brawls.
A 2009 match between Bosnia-born Amer Delic and world number three Djokovic was the catalyst for a melee between groups of rival fans who hurled chairs in the beer garden outside centre court, knocking a woman unconscious.
Djokovic, the 2008 champion, has appealed to fans in both camps to behave during his match against Dodig, who defeated big-serving fellow Croat Ivo Karlovic.
"We are very good friends actually off the court, all of us Serb and Croatian players. There's no reason to create any kind of bad feeling about our countries," Djokovic said after beating Spaniard Marcel Granollers.
"We did have problems in the past, but that doesn't concern us. We are athletes. We are friends off the court... Hopefully nothing will happen."
Having held peaceful tournaments throughout the Australian Open's more than 100-year history, organisers were caught off guard when Serb and Croat fans attacked each other with bottles and flags, which resulted in 150 people being evicted.
ETHNIC TENSIONS
Sports events in Australia, long a popular destination for migrants from eastern-bloc states, have often become battlegrounds for ancient ethnic tensions.
Violent clashes became commonplace in Australia's soccer leagues, where clubs were traditionally founded along ethnic lines and nationalistic tensions simmered between rival Serb, Croat and Greek fans.
Police and organisers declined to comment as to whether security efforts would be bolstered ahead of the Djokovic-Dodig clash.
"Every tennis match during the Australian Open (is) subject to risk assessment by police," police superintendent Rod Wilson said in a statement.
"No matter who you are or where you're from, if you behave inappropriately you will be dealt with by police."
Forty-seven people were ejected from the tournament on the first day's play on Monday, police said, mainly for unruly behaviour.
More than 600,000 people are expected to attend the January 17-30 Grand Slam.
