Bryan Robson can thank his old club for playing his strikers back into form.
Before last night, Geoff Horsfield was the only one of West Brom's six frontmen to have hit the target.
By the final whistle, three of his fellow attackers were up and running for the season as City exited the Carling Cup at the second-round stage.
The only one to miss out was Kanu but he came off the bench to show the quality touches that the Baggies will need to call upon if they are to defy Premiership relegation for a second time.
The intervention of the gangly former Arsenal man in the last half hour proved too much for the Bantams, who had just about stayed in contention up to that point.
Kanu laid on killer passes for the third and fourth goals which gave the final scoreline an emphatic look which had seemed unlikely midway through the second half.
Colin Todd made only the one change from the Yeovil draw, covering the enforced absence of Andrew Taylor by recalling Darren Holloway over Lewis Emanuel and switching Richard Edghill to the left.
Bobby Petta was given another chance after his poor show at the weekend - and in one early attack produced more than he had in total in the previous game, cutting in from the left to drift parallel with the penalty area before rifling a right-footer over the bar.
Steve Schumacher fired wide after a great tackle on Neil Clement by Lee Crooks and City seemed to be settling nicely against their Premiership hosts.
City were nearly caught sleeping at the back when Diomansy Kamara's quick throw-in found Rob Earnshaw, who drilled into the side-netting. But there was no let-off after 23 minutes as Nathan Ellington notched his first goal since a £3m move from Wigan. City old boy Darren Moore, made captain for the night, nodded clear and Darren Carter's volleyed pass sent Ellington clear. His pace was too hot for the two centre halves and the finish from 15 yards was deadly.
Lifted by the goal, the home side began to look the part and Kamara's 31st-minute cross-shot out of nothing troubled Russell Howarth, who needed two grabs at it.
But the Senegal international was just warming up and within a minute he had doubled West Brom's lead.
Questions had to be asked about the absence of any marking at all as Kamara was given the freedom of the six-yard box to nod home Jonathan Greening's free-kick after the winger had been brought down by Richard Edghill by the corner flag.
Earnshaw thumped inches over after being set up by Richard Chaplow and there was still little sign of any fightback, with Dean Windass and Andy Cooke making little impression on the Albion back four.
Then suddenly, in the last of the three added minutes, City grabbed an unexpected lifeline. Holloway hoisted a left-footed cross towards the penalty spot, where Schumacher leapt above Steve Watson to steer a firm header beyond the static Tomasz Kuszczak.
It was the 21-year-old's first goal of the campaign and gave City something to play for in a game that had looked beyond them.
The goal also breathed some life into the away fans, who offered their side plenty of encouragement for the second half - as well as taking a noisy pop at Robson.
Robson was concerned enough to replace left winger Jonathan Greening with Kanu - a switch that altered the pattern of the game.
Petta and Earnshaw both traded wild efforts before the Welsh international showed Holloway a clean pair of heels and drifted a cross-shot to the far post, where Howarth superbly finger-tipped away.
It was Robson's change of tactics that paid off after 73 minutes as Kanu, operating just behind the front two, slid an inviting pass through City's offside trap.
As the defence hesitated, Ellington motored clear and beat Howarth with a well-disguised chip from 18 yards.
City needed a quick response to keep the tie alive and almost provided it as Edghill's cross-field ball was volleyed over by Windass. That was as close as they got, though, as West Brom sealed the victory four minutes later.
Again Kanu was the mastermind, rolling the ball between Mark Bower and Edghill and Earnshaw slid in to do the rest.
The contest was over, although there was still time for Iain Williamson to prove that common sense is a thing of the past when it comes to refereeing.
Left back Martin Albrechtsen got the wrong side of Windass and nudged him over just outside the Baggies penalty area.
Williamson consulted with assistant Paul Danson and, despite the protestations of both players, reached for his red card.
Given the scoreline and the little time remaining, it was a harsh verdict.
West Brom thought they had a fifth goal through Kanu - and even the Tony Christie celebration music blared out - but it was ruled out.
City will have pocketed around £30,000 from the gate receipts and can shrug this off for the more important league tests ahead. Robson, though, may view last night as a launchpad.
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