Croatia coach Niko Kovac Monday said he was confident that his rejuvenated squad would have a good performance in their key Euro 2016 qualifier this week against Bulgaria.

"It will be a real challenge...the boys know it is a key match. It is good to have a positive result away ... If we will have a good approach I believe our chances are good," Kovac told reporters.

He was referring to Friday's match in Sofia, while on October 13, Croatia host Azerbaijan.

Croatia will be without three key players for the two matches.

QPR's Niko Kranjcar, midfielder Milan Badelj of Fiorentina and Getafe's Sammir are all absent from the 25-man squad.

But Kovac has called up three uncapped players in Dinamo Zagreb's midfielder Domagoj Antolic along with defender Ivan Tomecak and midfielder Marko Leskovic, both from Rijeka.

On Monday Kovac stressed he had "started with the process of (squad's) rejuvenation."

"Our goal is to give youngsters a chance to mature with their older colleagues."

Kovac had earlier called up 18-year-old Alen Halilovic of Barcelona B and most recently Andrej Kramaric, 23, from Rijeka.

Croatia play in Group H which apart from Bulgaria nad Azerbaijan also includes Italy, Norway and Malta.