"I can't see any difference between friendlies and official matches. We're focused on the next game against Costa Rica," said the Roma full-back on Saturday.

"We are a rather young team, but lack of experience won't be a problem. All our players have deserved being here due to their performance and their personal qualities."

He added that being the captain of his team was a source of great motivation.

"I'll ask my teammates to relax and enjoy. We have deservedly qualified for the World Cup. Perhaps, we don't even know what we are capable of. Playing for the national team is a huge honour for me," Kolarov said.

Serbia will face Costa Rica in their first World Cup match in Samara on Sunday.