On a night when new signing Aymeric Laporte made an impressive debut, goals from Fernandinho, Kevin De Bruyne and Sergio Aguero, the Blues controlled the game from start to finish with yet another impressive display.
On a chilly evening at the Etihad, the Blues quickly warmed to the task against a Baggies side who arrived with just one in 22 Premier League games.
Pinning the visitors back in their own half, City dominated from the kick-off, looking for an early goal and only alert keeping from Ben Foster kept the scores level as he foiled a Raheem Sterling cross that seemed destined for the predatory right boot of Aguero.
Then David Silva appeared to be caught just inside the box but referee Bobby Madley waved the appeals of the City skipper away.
Then the peerless De Bruyne tried to catch out Foster with curling shot instead of the cross he appeared to be shaping up for but the Albion keeper beat the shot away.
It was all City with the visitors clinging on until finally, on 19 minutes, the deadlock was broken.
Inevitably, De Bruyne was again the architect as he spotted Fernandinho’s run and sliced the Baggies defence open with a precision pass that the Brazilian slid past Foster.
De Bruyne then should have doubled the lead after Aguero’s clever flick sent him clear on goal, but he scuffed his shot and Foster saved with his feet.
Then the Belgian grazed the bar with a rasping shot from 20 yards before again working Foster with a side-footed effort from 15 yards.
City lost skipper Silva just before the break with what looked like a hip problem as the visitors made it to half-time just a goal down and still in the contest - despite Ederson barely touching the ball at all.
The Blues came close to a second moments after the restart as Ilkay Gundogan glided past two challenges before feeding Sterling who checked inside and curled a shot just over the bar.
Then Aguero’s cheeky back-heel almost caught Foster out, but the second goal was proving hard to come by.
Albion's goal was living a charmed life as City turned the screw until, at last, a thoroughly deserved second goal arrived midway through through the second period.
De Bruyne powered forward and despite a crude challenge from James McClean, passed it to Sterling who returned the pass for the Belgian to sweep home from close range - it was no more than he deserved after yet another masterful performance - it was also the Blues' 100th in all competitions this season.
Moments later De Bruyne spotted Foster off his line and almost chipped the ball in from maybe 50 yards out but Foster scampered back and tipped the ball over.the bar.
Brahim Diaz and Bernardo Silva went close in the time that remained before Aguero applied the icing on the cake with a third a minute from time with a deft chip over Foster following good work by Sterling.
All in all, a comfortable night for the Blues.
Star man: Kevin De Bruyne
What it means:
With United losing to Spurs, the Blues have restored a 15-point lead at the top of the Premier League.
City travel to Turf Moor to face Burnley in Saturday’s early lunchtime clash.
Then, a rare week of inactivity before Leicester City visit the Etihad a week on Saturday, before travelling to FC Basel in the Round of 16 Champions League first leg.