The Blues went 1-0 down at 44 minutes thanks to a goal from City’s Raheem Sterling and Sergio Aguero had a chance to double his side’s lead but missed a penalty just before the break.
City then collapsed in the second half as Chelsea held strong with Hakim Ziyech equalising and Marcos Alonso getting a late goal to seal the win.
The victory meant Tuchel’s men claimed all three points to go third in the league table and forced City to wait to snatch the league title.
Tuchel told Sky Sports: “We were more or less equals in the first half, in the last five minutes we almost gave it away completely.
“If they scored the penalty it was over before it started and we would have no chance to come back.
“But absolutely impressed by the reaction and performance in the second half, we deserved to win the second half.
“If you want to steal all three points at the Etihad you need a bit of luck, moments and decisions from the referee.
“But we had many half chances in the second half and so a big congratulations to the team for their performance.”
And the Chelsea boss also heaped praise on Timo Werner, who faced a nasty challenge from Sterling with many fans arguing the England star should have been given a red card.
“In the last week he’s really adapted well to the situations,” said Tuchel. “The way he works he’s relentless. He really wants it and I am very happy with his performance today.”
The two teams will face each other once again in a few weeks time in the Champions League final.
Sign up to the Mirror Football email here for the latest news and transfer gossip.