Why Chelsea have form AND history on their side going into City clash
History repeats itself. The first time as tragedy, the second as farce.
Not if you're a Chelsea fan, though.
And as Fernando Torres' smile lit up Stamford Bridge yesterday, for the first time in five months, it felt like 2009 all over again.
Three years ago, the figure of Guus Hiddink filled the Chelsea dug-out, the Dutchman who turned round a club heading for the rocks under Luiz Felipe Scolari.
Roberto Di Matteo will probably never have the same status or managerial stature as Hiddink.
After all, Hiddink has led Holland and South Korea to World Cup semi-finals, steered Real Madrid and Valencia, succeeded with PSV Eindhoven, Russia and Australia too.
Di Matteo, by contrast, was sacked by West Brom barely a year ago, amid suggestion that he was not entirely the most hard-working man in the history of the game.
The Italian does, though, know what Chelsea are all about. And like Hiddink has adopted a big tent approach, getting everybody onside.
Four wins out of four, a growing sense of determination and optimism, the ability to rotate for the good of the squad without causing discontent.
Hiddink, remember, turned round that season of imminent decline, taking Chelsea from the cusp of catastrophic failure - by the demanding standards of Roman Abramovich - to an FA Cup win and the brink of a Champions League final place that would have been theirs had any referee other than Tom Henning Ovrebo been in charge against Barcelona.
Now, under Di Matteo, the direction of travel is starting to look very reminiscent of that brief Hiddink reign.
Maybe it is because, like Hiddink, the Italian knows that he is only here for the short-term, that he cannot be "sacked" as manager before leaving on his own terms.
More probably, though, it is because he has done what Hiddink did - and put square pegs in square holes.
The key, unquestionably, is the change of mood.
Getting rid of Andre Villas Boas may have been brutal blood-letting but it was necessary as well, a cathartic act.
Under the Portuguese, the splits were growing deeper and wider, a club in a fearful mess.
All now seems changed, calm, composed. And while the summer of upheaval, of the long-predicted purge of the old guard, is still likely to take place, everybody appears to be buying into Di Matteo's formula.
Confidence is the most fragile yet vital commodity in football of course. It can build and build, only to disappear with one bad decision, one mistake, one piece of misfortune.
Yet it can turn for the better on one moment too.
For evidence of that, look at Torres, 151 days without a goal before slotting home from Raul Meireles' pass and who then got a second within 18 minutes against Leicester.
Whether Di Matteo can stick with Torres against Manchester City on Wednesday, rather than reverting to the power football embodied in Didier Drogba, is another issue, perhaps the biggest one.
After all, having shown he does know how to score, the Spaniard will be desperate for another chance to prove it, against far more serious opposition - albeit a side suffering their own crisis of faith and who must win to prevent that inexorable feeling of the title slipping from their grasp.
Asked about the Spaniard, Di Matteo said: "Fernando works so hard for the team. He is a great team player and you get rewarded in life when you work hard."
It represents a huge opportunity for a Chelsea side who, surely, would have expected to be viewing their trip to the Etihad with trepidation.
Suddenly, all is different. It will be Chelsea who go into the game with momentum and belief, City who will be anxious and nervy. Strange game, football.
Read Martin Lipton on Chelsea every Monday - and follow @MartinLipton on Twitter