While Manuel Pellegrini's men - beaten by Burnley last time out in the Premier League before suffering a UEFA Champions League exit at the hands of Barcelona - cut the gap to leaders Chelsea to three points, the focus fell firmly on referee Neil Swarbrick.
The key talking point unfolded in the second minute at the Etihad Stadium, when Wilfried Bony was fouled outside the box by Craig Dawson, with Swarbrick allowing play to go on before Gareth McAuley dispossessed the Ivorian.
Swarbrick then awarded a free-kick for the initial infringement, but inexplicably sent McAuley from the field - despite Dawson appearing to concede that he should be the one to go.
City made the extra man count as Bony opened his account for the club in the 27th minute and Fernando capitalised on some shoddy defending to double the lead before the interval - chalking up the club's 1000th Premier League goal in the process.
Boaz Myhill was excellent in the face of sustained attacking pressure after the break, while Frank Lampard and Bony struck the woodwork - as did Saido Berahino at the other end - before David Silva wrapped it up late on.
The champions' task of retaining their title remains a tall order, with Chelsea - who face Hull City on Sunday - having two games in hand, while West Brom still cannot rest easy in their survival bid.
Tony Pulis had to reorganise quickly after McAuley's early dismissal as City dominated possession and territory.
Myhill would have expected to be kept busy, but the goalkeeper's first major test did not come until the 24th minute, when he kept out Silva's powerful strike.
As tight and compact as West Brom were, City found a way to unpick the lock four minutes later as Fernando's deflected shot was brought down by Bony and rifled into the net from 10 yards.
Pulis' side rarely emerged from their own half and Myhill had to be alert to tip a Jesus Navas effort over the bar, but there was little he could do when slack defending allowed Fernando to make it 2-0.
Jonas Olsson's poor attempted clearance forced a save from his own goalkeeper, with Fernando on hand to tap in the loose ball for a landmark City goal.
The pattern of play continued after the interval - the hosts in control, pressing and probing for openings against an organised but embattled 10-man side.
The division's top scorers were frustrated by the woodwork twice in one attack, as Lampard struck the upright before Bony's untidy follow-up was hit into the ground and looped onto crossbar.
Berahino hit the underside of the crossbar with a close-range header - preserving a 100th Premier League clean sheet for Joe Hart - and City responded to that scare by extending their lead further with Silva deflecting Stevan Jovetic's shot in.
Despite the home side's celebrations, the focus will fall firmly on Swarbrick, whose decision to dismiss McAuley will surely be overturned.
