Former Australia boss Frank Arok believes his home country, Serbia, could cause the Socceroos real problems from set-pieces at the World Cup.
After facing Germany and Ghana, Australia meet Serbia in their final Group D game and the match could prove vital in what is considered one of the stronger groups in this year's competition.
And Arok, who managed Australia from 1984 to 1990, believes preventing Manchester United's Nemanja Vidic and Chelsea's Branislav Ivanovic from providing an aerial threat from set-pieces will be the key to success.
"It will be decided by corner kicks and free-kicks," he told the Sydney Morning Herald. "If I was the Australian coach, I would put them under pressure, maybe play two small, quick, guys up front and spread it out, because the big guys at the back for Serbia don't like that.
"The big danger for Australia will be the two guys [Vidic and Ivanovic] who play in England. They don't have good strikers, but these guys are so dominant in the penalty area. They'll come up for corners and free kicks, and they are so dominant in the air. It's going to be a close game, but an ugly game, and one free-kick can decide everything."