Vieira, however, does have form in this competition, winning the famous trophy four times with Arsenal and scoring the decisive goal in a penalty shoot-out on the last of those occasions in 2005.
But with City's ?50million strikeforce of Mario Balotelli and Edin Dzeko struggling to trouble a team 59 places below them it was left to the veteran Vieira to score with headers either side of half-time.
That gave Roberto Mancini's side the breathing space they needed, having weathered an early storm, and substitute Carlos Tevez, Dzeko and Micah Richards all scored in the final six minutes to distort the scoreline somewhat.
It may have been a different story had Karl Hawley's shot from the left side of the box gone in rather than striking the inside of Joe Hart`s far post when the game was goalless.
City now face a delayed fifth round tie at home to Aston Villa.
Source: PA
Source: PA