Russia finished second in Group A after a 3-0 loss to Uruguay on Monday and will take on Group B winners Spain at Moscow's Luzhniki Stadium on Sunday.

"We will face serious opponents - Spain are three-time European champions and the 2010 World Cup winners," said Degtyarev.

"They have huge experience. However, in my opinion, Spain don't play to their full ability and don't show their maximum results at this tournament. The round of 16 match will be held in Moscow, at the Luzhniki Stadium, so our trump card is the 12th player, the powerful support from the stands."

He added that players needed to prepare well for the game, and fans should support them.

"It's early to criticise the Russian national team after the 3-0 loss (to Uruguay last night). There are defeats, draws and wins in sports. Let's wait for the end of the tournament and then sum everything up," Degtyarev said.