The Russian international goalkeeper had conceded a goal in his previous 43 Champions League matches, excluding qualifiers, an ignominious spell stretching back to a game with Arsenal in November 2006.
Yet the 31-year-old at last ended the miserable run as Moscow earned their first home win of the campaign to keep their hopes of reaching the knockout stages flickering while shattering Benfica's chances.
"Of course, we congratulated him after the match," said CSKA coach Viktor Goncharenko. "All of the lads tried their best in the last part of the game to close any gaps and make sure Igor kept that clean sheet!"
Georgi Schennikov had put CSKA ahead after 13 minutes with a left-footed finish, having been assisted by Bibras Natcho's short through ball that shredded Benfica's backline.
The visitors' troubles worsened after the interval as defender Jardel then clumsily deflected a cross by CSKA's Vitinho into the back of his own net after 56 minutes.
CSKA's win has put them in third place in Group A on nine points, the same as Basel, who moved into second place by beating leaders Manchester United 1-0. The Russians face United, who have 12 points, at Old Trafford in their final group game.
Yet the result ensured that former European champions Benfica, still without a point, are now certain to finish last.
(Reporting by Gabrielle Tétrault-Farber; Editing by Ian Chadband and Toby Davis)
