Jose Mourinho's special aura saw him lead Chelsea to unprecedented success and, following his departure, the club went through seven managers. It was never the same without him.
The Portuguese manager went on to maintain his credibility by dominating Italian football with Inter Milan, and Spanish football with Real Madrid. His time at the Santiago Bernabeu club saw the end of Barcelona's long term stranglehold of La Liga.
Meanwhile, Mourinho's last breeds of players at Chelsea continued to prove terrific in English football. He had built his winning machine around Petr Cech, John Terry, Michael Essien, Frank Lampard, and the scrupulous Didier Drogba.
These players formed the seal of Mourinho's unmatched managerial prowess as they dominated Europe in 2012 - five years after he had left.
Now, the self acclaimed 'special one' has returned to the club with whom is is most associated. Unfortunately, the opening season of his second spell wasn't as successful as the first - as Chelsea ended up trophyless last term.
Many football lovers have argued that the Portuguese wouldn't be as successful as he was between 2004 -2007 this time around. Some said he shouldn't have returned. Others claimed he had luck on his side during his first spell.
During this period Mourinho was able to establish Chelsea as an unbeatable force at home. He was also praised for his solidity in defence, and his counter attacking approach - which could break apart the Barcelona of those days. Then, it didn't take long for him to work out who his vital players would be.
However, in his second spell, Mourinho has taken time to develop his new set of generals; hence the story of last season. After a very successful transfer window, Mourinho has now assembled a Chelsea team which has the potential of dominating England and Europe for the next five years.
Young players like Willian, Eden Hazard, Oscar, Cesc Fabregas, Diego Costa, Nemanja Matic, and Thibaut Courtois are already announcing themselves in the Premier League.
With the 3-0 win over Tottenham on Wednesday, December 3, this Chelsea side equalled the previous 23-game unbeaten record earlier solidified by Mourinho's first set of generals. And, despite the blip at Newcastle that soon followed, they are clear favourites for the Premier League title.
In Europe, Chelsea are among the leading contenders to win the competition, with arguably only champions Real Madrid and Pep Guardiola's Bayern Munich having greater prospects.
Having gone so close to winning both the EPL and UCL last season, with an inferior team, I really do think Chelsea can scoop both prizes this season if they continue in this top form.
Mourinho still has so much to prove in the game of football. He is already amongst the game's great managers, and he is only 51.