Abramovich wasted no time on Wednesday sacking Italian Roberto Di Matteo three months after he led them to their greatest night by lifting the European Cup in Munich.
Di Matteo's crime, besides never being Abramovich's first choice as coach, was that Chelsea had hit a blip with two wins out of eight games in all competitions.
Their 3-0 defeat at Juventus on Tuesday leaves their qualification for the last 16 of the Champions League hanging by a thread and out of their own hands.
By contrast, Manchester City's exit from the Champions League at the group stage for the second successive season represents poor return for the hundreds of millions of pounds invested in the club since Sheikh Mansour bin Zayed Al Nahyan bought it, and could be regarded as a far greater failure.
Mancini, who guided City to their first English league title for 44 years last May, has failed to inspire a victory in any of their five Champions League matches this season, and with three points from three draws, City will either finish bottom or third in the group.
To avoid last place, they will have to beat impressive Borussia Dortmund, already assured of topping the group, in their final game in Germany on December 4.
If they do that and finish above Ajax Amsterdam, City will qualify for the Europa League but that trophy, while prized by some, is very much an unwanted consolation prize for Europe's richest and most ambitious clubs.
Mancini told reporters after the match that despite their elimination he was not worried about losing his job.
"No, why, why? I don't fear this," he said. "If we think we can win the Champions League after two years we are crazy."
It took Abramovich nine years to see the European Cup delivered to Stamford Bridge but while the trophy arrived, little kudos and respect followed.
Chelsea are widely regarded as the luckiest winners of the trophy, seemingly guided by divine intervention when they needed it most.
City have hardly looked like winning a match in the competition over the last two seasons, never mind the competition itself and, for that, Mancini must accept his share of the blame.
FAILED GAMBLE
While Di Matteo gambled and failed against Juventus by leaving striker Fernando Torres out of his starting line-up and playing with creative midfielder Eden Hazard as the front-man, Mancini gambled on a three-man defence against Real and paid the price.
Real scored in the 10th minute when Karim Benzema was left unmarked, and City were lucky not to be five or six goals behind by the time Mancini reshuffled his defence with four at the back.
Even though they improved after that and were better in the second half, equalising with a Sergio Aguero penalty in the 73rd minute, City have had a poor campaign and have looked unconvincing for most of the time, almost as if they did not belong among the elite.
Along with Qatari-owned Paris Saint-Germain, City are valued as one of the two richest clubs in the world, even richer than Real Madrid,
