For the second time in less than a month, he got the better of Pep Guardiola.
At the time, Guardiola had misunderstood his tactics with a heavily modified squad that had the chance to avoid a loss heavier than the 1-0 score.
On this occasion, City had the game and the Premier League title in their hands.
A Chelsea collapse just before half-time saw Raheem Sterling give the chosen champions the advantage, while Sergio Aguero withstood a penalty to effectively kill the game.
The Argentinian’s sad Panenka gave Chelsea a lifeline – but the real turning point was Tuchel’s team speech at the break.
The city has gone from leadership to leadership.
Hakim Ziyech and Christian Pulisic were much more effective playing higher up the pitch to force City on the back foot. The excellent Reece James had Benjamin Mendy on a toast.
What was most impressive was Tuchel’s in-game management after seeing his side struggle to break City’s defense in the opening 45 minutes.
He tweaked it and with that, the game was turned upside down.
Ziyech’s weak training from the edge of the box evened the scores after Moroccan pressing pulled Rodri away from possession.
There would have been few complaints from Chelsea if he had indicated the location – but it was not a clear and obvious mistake on the part of the manager.
City were still protesting as Chelsea set off in search of a winner.
Marcos Alonso’s lob bounced off just the wrong end of the post – but when the defender ran on a Timo Werner’s cross deep in the stoppage time he wasn’t wrong.
The Chelsea bench erupted, as Guardiola and his staff continued to voice their grievances with fourth official Jon Moss.
Of course, that makes little difference to City’s season.
They will always be crowned champions; the champagne is simply put on ice.
But Guardiola doesn’t like to lose, whatever the occasion – and certainly not against the same opponent in quick succession.
Back-to-back defeats to Tuchel put City’s coach on the back foot ahead of the Champions League final.
Of most concern will be the fact that he appears to have found a solution to the issues that plagued his side in the Wembley semi-finals.
Ziyech and Pulisic were denied the opportunity to run behind and catch up with them at the counter.
City have defended deeper and had more body around Chelsea’s fastest runners, but Tuchel’s success so far has been his ability to adapt to different opponents.
Here he did it halfway – and while it certainly wasn’t a one-sided affair in the second half, Chelsea’s dominance of the ball in City’s half was notable.
And so another elite manager falls victim to the Chelsea boss; Guardiola and Zinedine Zidane both improved within days.
Jose Mourinho, Jurgen Klopp and Diego Simeone – on two occasions – have failed to deal with Tuchel since taking control of Stamford Bridge.
It’s now also two wins against Guardiola – and would he bet against it becoming three in Istanbul?
Aguero does not make a good impression
If Aguero was hoping to stand in the window, this really wasn’t the day for that.
His contact with an open net was so heavy that it would have been considered an all-time horror dud, if Sterling hadn’t finished.
Then, with a penalty to put the game to bed, he messed up his Panenka, the only consolation being that there were no fans on the pitch to see him.
Tuchel is certainly a fan of the Argentine and Chelsea are interested in signing him as a free agent this summer. But it was not his day.
It reaches a point where it’s not bad luck, it’s just sloppy play.
Timo Werner saw two goals ruled out for offside to add to one that was called off against Real Madrid midweek.
But the German can hardly deplore his luck.
Rather, it was because of his repeated failure to get back into place.
It’s maddening how many times he wanders offside when he should be playing off the defender’s shoulders.
His finish has let him down this season – but his sense of position is another pressing concern.