Aleksandr Kerzhakov netted in the first 10 minutes to give the hosts the lead in Moscow and, despite being on the back foot for most of the match, the Euro 2012 semi-finalists were unable to equalise and it finished 1-0.

Former England, Juventus and Real Madrid boss Capello admitted the game was tough but congratulated his squad for a battling performance to claim all three points.

"Today on the pitch I saw a Russia team that played with huge desire, huge commitment," Capello told reporters after the win. "It was a difficult match."

Portugal head coach Paulo Bento was melancholy in defeat and mused that his team were perhaps less focused than usual, which caused them to be error-prone in possession.

"Maybe we weren't as calm as we usually are," Bento said.

"Everyone can make mistakes, even the coach can make mistakes. We lost the ball a lot of times."

The win propelled Russia to the top of Group F with a 100 percent record after three matches, while Portugal remain second on six points with two wins and a loss.