Blackburn bag Petrovic from Partizan
The 22-year old Petrovic moved to Ewood Park from Serbian champions Partizan Belgrade, where he won three successive league titles and scored 17 goals in 70 games.
Rovers manager Steve Kean was delighted to have signed a player he said he had admired for some time.
"His record to date speaks for itself and he is exactly the type of player we have been looking to recruit," Kean said.
The 1.93 metres-tall defensive midfielder has also scored one goal in 16 internationals and was named in the Serbian Superleague's team of the season for two years in a row.
He is quick, adept and has good ball control for a big man, with most of his goals coming from long-range efforts or headers from set pieces.
Having secured a work permit for Petrovic, Rovers now face a race against time to clear him for their opening Premier League fixture at home to Wolverhampton Wanderers on Saturday.