Carlo Ancelotti won the double in his first season as Chelsea manager but even if he had repeated it in his second his tenure would not have been secure after failing in the only competition that interests the club's owner.
Whatever domestic success was achieved, Claudio Ranieri, Jose Mourinho, Avram Grant, Luiz Felipe Scolari and Ancelotti all found out that the club's failure to land the Champions League led to Roman Abramovich sending them on their way.
Grant was a John Terry penalty away from winning the ultimate prize in 2008 but having gone so close on his own soil after that Moscow final defeat by Manchester United, Abramovich sacked the Israeli three days later.
Even Mourinho, worshipped by the fans for turning the club into genuine giants of the game, was forced out after losing a battle of wills with the billionaire owner.
Only Guus Hiddink left entirely on his own terms, fulfilling his short-term contract after Scolari was sacked midway through his first season and returning to his job with Russia despite pleas from fans and players for him to stay.
Abramovich was less concerned as he scoured the game for a man who could bring him the ultimate trophy.
In Ancelotti he must have thought he had found him. Twice a European Cup winner as a player with AC Milan, the Italian went on to lift the trophy twice more as manager with the same club.
Things initially went well on the home front as he ended Manchester United's three-year domination of the Premier League, securing the title in spectacular style with a 8-0 thrashing of Wigan Athletic.
He followed up with an FA Cup final win over Portsmouth to give Chelsea their first double, but for all the joy of a Kings Road open-top bus parade, Abramovich remained on edge.
Having been Champions League semi-finalists at least in virtually every season since his arrival, an exit in the first knockout round was not what the Russian had in mind when he dug deep into his pockets to lure Ancelotti from Milan.
It did not help that the loss came at the hands of an Inter Milan coached by Mourinho, who went on to win the trophy with the club, just as he had with Porto before moving to Chelsea.
Not even Abramovich, however, could sack his manager after completing a domestic double so Ancelotti kept his job but with the unwritten proviso that Europe was his priority.
Ancelotti soon set about changing the squad, unloading established but ageing players and relying on a more youthful approach.
All seemed well when Chelsea won their first five League games of the season, scoring 21 goals in the process, but it was not long before the cracks began to appear.
Injuries to key players such as Frank Lampard and Michael Essien exposed a lack of depth while the controversial sacking of assistant manager Ray Wilkins seemed to destabilise the team.
A terrible run of form in November, December and January, the club's worst for almost 15 years, was regularly dismissed in Ancelotti's flailing English as "a bad moment" but effectively ended their hopes of domestic silverware.
Abramovich splashed a record 50 million pounds ($81.16 million) to add Fernando Torres to his stable but instead of kick-starting Chelsea's season, the faltering Spaniard just made things worse.
By continually picking the plainly out-of-form striker Ancelotti either had to upset either Didier Drogba or Nicolas Anelka by leaving them out or rearrange his tactics to include all three.
Neither approach worked and only in the final weeks of the season did the manager bite the bullet and start leaving Torres on the bench.
By then it was too late as the Champions League door had been slammed shut again, this time by Manchester United in the quarter-finals.
A late surge brought Chelsea back into the title race but having been outclassed in the decisive match against United, Ancelotti's goose was cooked and Sunday's defeat by 10-man Everton merely rubber-stamped the decision.
However, it was not Goodison Park, nor Old Trafford or even Stamford Bridge that ensured Ancelotti's exit, but Wembley.
Abramovich will surely find it almost unbearable when Barcelona and Manchester United run out for the Champions League final there next Saturday and will continue to hire and fire managers until he finally lands the big one himself.