Tuesday's result, following a 2-1 victory against Spartak in Milan two weeks ago, lifted the Italian champions to second in Group B with six points, four behind leaders Bayern Munich.

"It was important to win. Nothing else mattered. We needed the three points to make up for our poor start in the competition," Mancini was quoted as saying in La Gazzetta dello Sport.

Inter's win in freezing conditions in the Russian capital was their third in seven days, a sequence that included a 4-3 victory over city rivals AC Milan at the weekend.

"I think that the derby gave us a lift, boosted our confidence in our abilities," Mancini said.

"And by winning again today we showed that we've also made a big step forward psychologically."

Inter began their Champions League campaign badly, with back-to-back defeats against Sporting Lisbon and Bayern.

A win in their next match against Sporting on Nov. 22, however, will send them through to the knockout phase -- a huge relief to Mancini, whose much fancied team looked in danger of an early exit.