Having needed two attempts to put paid to feisty Championship outfit Leicester, the Blues have a second chance to see off League One Notts and earn a home tie with Aston Villa thanks to a sublime finish from Bosnia striker Edin Dzeko.
Dzeko’s first, vital goal in a City shirt since arriving from Wolfsburg keeps Wembley in sight but, fine strike that it was, the equaliser owed much to a cracking centre from man of the match Micah Richards.
There were barely ten minutes left when he sped down the right flank, with Neal Bishop’s opening goal for Notts threatening an embarrassing giantkilling against the club who were their last top-flight victims in 1991.
Recalled hero Richards even had chance to put in a match-saving far-post challenge on Notts skipper Mike Edwards before limping off to leave his team-mates to make sure of another replay at the City of Manchester Stadium.
The scene was set for one of those Cup upsets that City fans once feared so much whenever their club was drawn away to a so-called lesser team, and 59 places in the League is probably even more of a disparity these days.
Toss in the fact that the pitch had been given a good roughing up by the local rugby union team - who left their mark in more ways than the extra white lines - and City’s status as a prized scalp, and it was never going to be easy
City’s afternoon might have been much more comfortable had Yaya Toure made decent contact with Micah Richards’ early cross, but his stretch of an attempt carried little power and Stuart Nelson weas able to stick out a boot to save.
Or if Dzeko, relishing his first taste of the FA Cup after signing too late for the Leicester replay in the last round, had been able to capitalise on a half-chance that defender Christian Pearce whipped off his toes.
Pearce did even better a few minutes later with a superbly-timed penalty area tackle on the Bosnian that would have conceded a spot kick if mistimed, and his attitude summed up County’s spirited approach.
Inevitably City missed the reassuring presence of skipper Carlos Tevez, whose weekend off left Gareth Barry to don the armband, although Mancini installed David Silva on his bench in case of emergency, and in the end needed to break the glass.
Hearts were in mouths when Alan Gow curled a free kick wide of Joe Hart’s left-hand post with Notts’ first attack of the tie, but thereafter - with Patrick Vieira patrolling midfield with some authority - there was little danger.
Not until the 58th minute that is, after a tussle between Pablo Zabaleta and Lee Hughes in which the veteran striker argued for a penalty but had to settle for the corner that still brought about Bishop’s goal.
Alan Gow’s flag kick arrowed towards the near post and Bishop, a non-league journeyman for much of his career, rose for a glancing header that took the ball past Hart and under the bar with Zabaleta getting his head to it too late.
City had their chances to restore the balance. Dzeko lofted a header under pressure onto the roof of the net and Barry perfectly caught a half-cleared corner only for Nelson to fingertip his shot over the bar.
But Notts responded and, with a precious goal to defend, were in no mood to concede their place in the history books until Richards sent in that pinpoint cross for Dzeko to despatch with a confident, classy left-foot volley.
