Was this the night the blue moon began rising again towards a first league championship since 1968? With Manchester United going down at Wigan Athletic this emphatic win, studded with a supreme display from Sergio Agüero and Carlos Tevez's first league goal since May, closes the gap to five points for Manchester City to Sir Alex Ferguson's men.
By Saturday afternoon the deficit could be reduced further, to two points, as Roberto Mancini's side travel to Norwich City for the early kick-off, while United host Aston Villa on Sunday afternoon. A 20th league title is still in their hands but despite Mancini's claim that City are still out of it due to United's "fantastic spirit" – surely his attempt at mind games – nervous times are back: another slip and the title decider could again be the Manchester derby here later this month.
For the first time since 21 September Tevez's name had been read out in a Roberto Mancini first XI, the Argentinian also making what was only a second league start for City in this troubled season. He would end his evening after 63 minutes having illustrated what the Blues have missed, his ability to operate between the lines as impressively as when he was captaining City and scoring 24 times last season.
It was Agüero, Tevez's countryman, who would take City into the interval a goal up, giving his side their first lead in the league since 3 March, when the Bolton Wanderers Gretar Steinsson's own goal set City on their way to a 2-0 win.
Agüero's 25th goal of an impressive debut season at the club came when he collected possession in midfield, brushed off Keith Andrews, and slotted a 20-yard shot to Ben Foster's right.
Roy Hodgson's side had their moments, but these were few, with two featuring Joleon Lescott being embarrassed. First, Shane Long's speed left him trailing before the No9 turned into Vincent Kompany and was barged off the ball. Then Lescott allowed a high ball to bounce, despite being in prime position beneath it, and he was fortunate that Long again failed to profit. And there was also a menacing cross fed in by Simon Cox that swept before Joe Hart but lacked the finish, and an Andrews effort that went straight at the keeper.
That City had rediscovered their quality was evident throughout. As the suspended Mario Balotelli watched from an executive box, a smooth move went from Samir Nasri to Agüero back to Nasri then into Tevez, who played a one-two with the Frenchman before he unloaded a bullet of a shot that was just too high.
As the half closed, a Ben Foster howler which saw him carrying the ball over the line for a corner had the fans behind his goal singing how he was "England's No5". But it was the City No32 who had impressed so far, and he would be the initiator of his side's second, nine minutes into the second half.
After Tevez's attempted ball towards the West Bromwich area was repelled, it arrived at Nasri, and his pass into Agüero was placed across Foster for his second.
As a celebration not seen in this stadium for a while – the Poznan – broke out, City again moved upfield, and Nasri had a golden chance that would have secured a first league win since Chelsea were beaten here three weeks ago.
The Frenchman's effort was wide and when Mancini tore into his side after West Brom forced a corner, the proof that City were emerging from their costly poor run was about to be confirmed.
After an Agüero attempt from the angle was cleared, Tevez's moment arrived. Nasri played Agüero into the area and, from close to the line on the left, he pulled the ball back to Tevez: his careful finish made it 3-0 and was followed by a calm celebration, and his removal by Mancini – his work done for the night.
David Silva then scored his first league goal since 18 December. For this, Jonas Olsson dawdled, was robbed by Agüero who played in the Spaniard, and he moved at the advancing Foster before chipping a sand-wedge of a finish over the keeper.
Now, with Tevez and Silva returning to form, Mancini also hopes Yaya Touré can be restored to the side after a leg injury. "He took a knock on the knee against Arsenal. I don't think it's a serious injury," the manager said of the midfielder. "Maybe for Saturday he will be ready."