Russia will face Saudi Arabia in the opening match of this summer's tournament on June 14.

"I think Russia will be the favorites in the match against Saudi Arabia, but you saw today's game with your own eyes, we can make an obvious conclusion: it is very difficult to play this team. Moreover, Russian players have suffered a lot of injuries over the past year. One of them is Kokorin. It seems to me that Kokorin was very important for the Russian team. Thus, his injury has weakened the team," Mancini told journalists after Italy's 2-1 win over Saudi Arabia in Monday's friendly in the Swiss city of St. Gallen.

Kokorin tore cruciate ligament in his right knee in mid-March. The 27-year-old has been capped 48 times for Russia, scoring 12 goals since he made senior debut in 2011.

Russia will host its first FIFA World Cup from June 14 to July 15. The fixtures will be played at 12 stadiums across 11 cities. The hosts will face Saudi Arabia, Egypt and Uruguay in Group A.