The bottom of the table Baggies, forced to play for 73 minutes without dismissed Danish defender Thomas Gaardsoe, snatched an unlikely point through a late own goal from Richard Dunne.
City were stunned in the 84th minute when Paul Robinson's long throughball struck Dunne and eluded advancing goalkeeper David James before trickling into an empty net.
The effort, which was West Brom's only attempt on goal, earned Bryan Robson only his second point in eight Premiership matches since he succeeded Gary Megson as manager.
City, who had lost three of their previous four Premiership matches, had looked set to return to winning ways, even though they gave an unconvincing display.
Nicolas Anelka's stunning free-kick had appeared to have given them three much-needed points.
Albion, beaten 4-0 and 5-0 in their last two matches, set out their stall to frustrate City as they began with a defence-minded 4-5-1 formation.
However, that game-plan lay in tatters after only 17 minutes when Gaardsoe was dismissed for hauling back Robbie Fowler who was bursting through on goal.
City broke the deadlock in the 32nd minute after Andy Johnson had handled on the edge of the penalty area and Anelka drilled a free-kick over the defensive wall.
It was a delightful strike - Anelka's seventh goal of the season - which left goalkeeper Russell Hoult rooted to his line.
City dominated the opening period, but only occasionally troubled Hoult.
And it was a similar story in the second half as the one-way traffic continued, with Hoult making excellent saves to deny Shaun Wright-Phillips and Fowler.
The visiting fans turned on Robson when he brought on striker Rob Hulse for Zoltan Gera ahead of top scorer Rob Earnshaw who remained on the bench.
They called for Robson's sacking and sang the praises of former manager Megson.
Then completely out of the blue the Baggies equalised thanks to Dunne's unfortunate blunder.
Moments later Hoult came to the visitors' rescue again with a brilliant save to keep out Fowler's volley as City were forced to settle for a point.