City's laboured challenge for a place in the last 16 will reach a potentially dramatic conclusion on Wednesday as they travel to Italy for their decisive final Group E match at Roma.
Pellegrini's men kept their seemingly doomed hopes of progress alive with a stunning late 3-2 win over Bayern Munich in their last game, thanks to a brilliant hat-trick from Sergio Aguero.
City had collected just two points from their opening four matches in the competition and had looked to be staring at a premature group-stage exit for a third time in four seasons.
But CSKA Moscow then snatched a draw against Roma to keep City in the equation and Aguero - almost single-handedly - did the rest.
City, Roma and CSKA are now all level on five points going into the final round of fixtures, with one qualification spot available behind Bayern.
There are numerous permutations, but basically City must win and hope CSKA do not beat Bayern, or get a score draw and hope CSKA lose.
Their hopes of achieving that are now much improved after City followed their remarkable victory over Bayern, when Aguero completed his treble with two goals in the last five minutes, with comfortable wins at Southampton and Sunderland.
Those results have reinvigorated their Barclays Premier League title defence after a frustrating spell in October and November, and confidence is growing.
Pellegrini said: "It has been important to recover the trust in the way we play and the way we play every day.
"Maybe before this week we were not in the crisis most people said, but it's still important to arrive at this moment of the season.
"In the Premier League I always say that December is the key month - to be as near the top of the table as we possibly can - and of course we have to try and play a new stage in the Champions League.
"So the more trust we have, the better for us and I think this is a good moment.
"Important players have come back to their normal performances and when those important players play well the team plays well as well."
City are hoping to have captain and defender Vincent Kompany and playmaker David Silva back for the trip to the Italian capital after spells out with hamstring and knee injuries respectively.
But the key man is Aguero
The Argentinian has been in outstanding form throughout the opening months of the season after overcoming the recurring muscular problems that hampered him during the second half of the last campaign and at the World Cup.
His performance against Bayern also added credence to Pellegrini's regular assertions that the 26-year-old can challenge the likes of Cristiano Ronaldo and Lionel Messi for the Ballon d'Or award in future.
Previously Aguero's lack of top-level performances on the Champions League stage had undermined his case, but Pellegrini believes he is good enough to maintain his current level.
"Sergio is a very good player," the Chilean said
"He must be - if he wants - in the five best players in the world.
"But it is not important to compare
It is important to try to demand Sergio is in the level he must be in football."
Source : PA
Source: PA