The Londoners abandoned their suicidal high line defensive strategy, sat deeper in defence and strangled the life out of Roberto Mancini's side who had started like champions, but after defender Gael Clichy's 58th minute red card, ended the match looking like many City teams of old: lost and confused.
Chelsea manager Andre Villas-Boas's insistence on his defenders holding their line some 40 or 50 metres from goal to give his team extra attacking verve has been exposed as largely unworkable, especially in the 3-1 defeat at Manchester United and the 5-3 home loss to Arsenal.
It cost them the first goal after two minutes on Monday at Stamford Bridge when Pablo Zabaleta found Sergio Aguero just inside City's half.
Aguero executed some exquisite skill before his pinpoint pass allowed Mario Balotelli to break free just inside Chelsea's half, and then score after a surging run took him past goalkeeper Petr Cech.
City totally dominated the next 25 minutes while Chelsea still defended high up the field but gradually, seemingly collectively reverting to type, began to defend much deeper.
Villas-Boas gave a hint that the players took the decision to drop back rather than him, when he told reporters: "In the first minutes, we suffered a lot and the players felt they needed to adjust.
"We started with a medium block defensively, but it was difficult for us and the players stepped back. Then they felt the confidence coming back to them. They were brave to adapt and we showed good strength of character to win this game."
SEVEN POINTS
Defeat would have left Chelsea 13 points behind City but they have now moved to within seven points at the top after 15 games.
Villas-Boas added: "Our objective was to shorten the lead at the top and to do that, we needed to beat City. We adapted to the circumstances, we felt how the game was going and deserved to get the win."
Victory certainly eased the pressure on the Portuguese after five defeats in a nine-match spell between the end of October and the end of November.
Now, following 3-0 wins over Newcastle United in the Premier League and Valencia in the Champions League last week which sent them into the last 16, Chelsea appear to be back on track.
The mystery was, why, when they started with a high line against Valencia before dropping deeper last week, they started with a high line again against City.
Although David Luiz, who has looked particularly vulnerable in the system, was suspended on Monday, John Terry and Branislav Ivanovic looked just as unhappy in the opening spell when City were in virtual total control.
Aguero should have doubled City's lead after 11 minutes but with David Silva playing some inspired football and Yaya Toure dominating play like Patrick Vieira did in Arsenal's title-winning era, it seemed City were set for all three points.
But gradually the game changed with Terry, Ivanovic, Ashley Cole and Jose Bosingwa all retreating back into what was clearly a more comfortable zone for all of them.
