Adam Johnson, making his first start since injuring his ankle in January, opened the scoring in the ninth minute and skipper Carlos Tevez doubled the Blues' advantage on the quarter hour from the penalty spot.
Second-half strikes from David Silva, Patrick Vieira and Yaya Toure completed the rout as City leapfrogged Chelsea in the table and moved further clear of fifth-placed Tottenham in the race for Champions League football.
Opening salvo: Adam Johnson (centre) fires City into the lead
Sunderland, meanwhile, have goneseven league games without a victory and need rapid improvement if theyare to avoid being dragged into the relegation dogfight.
With Tevez fit again having missedCity's 2-0 defeat at Stamford Bridge a fortnight ago with a groinproblem, Mancini opted to pair the Argentina forward with MarioBalotelli and drop Edin Dzeko to the bench.
Additionally boosted by the returnof Johnson, it was a positive-looking team selection which quickly paiddividends, the hosts making a lively start to the game before takingthe lead nine minutes in.
Playing a one-two with Toure downthe right, Sunderland-born Johnson received the return pass in the box,controlled the ball and then lashed it past Black Cats goalkeeper SimonMignolet.
Spot on: Carlos Tevez (left) nets a penalty to put City two up
Six minutes later Tevez latched onto a lofted ball from Silva and burst into the area, where he wasbrought down by Phil Bardsley.
Referee Howard Webb booked Bardsley and awarded a penalty which Tevez took himself.
Mignolet dived the right way and appeared to get a hand to the effort but it squeezed in off the upright and City were cruising.
They were on the offensive again soon after, Bardsley getting in a block to divert Tevez's strike behind for a corner.
Easy pickings: David Silva (left) makes the points safe for City
A Michael Turner handball earned City a free-kick which Aleksandar Kolarov could only send wide of the post.
Balotelli then tried his luck after being teed up by Tevez but Mignolet saved the attempt.
Sunderland were showing little signof getting themselves back into the match but had a rare shot at goalin the 37th minute when Asamoah Gyan sent in an effort from outside thebox which dropped narrowly wide.
Black Cats boss Steve Bruce replacedBardsley with Ahmed Elmohamady at half-time but City were soonthreatening again after the restart.
Silva played a deft chip into thebox and Johnson was there to shoot against Mignolet, although he wasincorrectly adjudged to be offside.
Lying down on the job: Patrick Vieira (grounded) scores City's fourth
Balotelli then drove into the area and brought a save out of Mignolet, before City's third goal arrived.
Tevez ran on to a long ball from Nigelde Jong and squared for Balotelli, whose shot ricocheted off Turner,allowing Silva to tuck home from close range.
Johnson was then taken off for Vieira, which swiftly looked like a stroke of genius on Mancini's part.
A minute after his introduction, theFrenchman was on the scoresheet, getting on the end of a Kolarov crosswhich deflected off Joleon Lescott.
Mignolet clawed Vieira's effort away but the goal was given and replays showed the ball had indeed crossed the line.
Having conceded twice in fourminutes, Sunderland looked utterly deflated and after Balotelli hadstung Mignolet's palms, it came as little surprise when City scoredtheir fifth.
Five-star show: Yaya Toure adds gloss to the scoreline with City's fifth goal
Lee Cattermole lost his bearings and gave the ball straight to Toure, who gleefully dispatched it over Mignolet and in.
Shaun Wright-Phillips came on for Silva and provided a cross for Tevez, who put the ball the wrong side of the post.
Elmohamady summed up Sunderland'safternoon when he rose unmarked in the box but sent his header offtarget, and Balotelli almost made it 6-0 in stoppage time with afree-kick that Mignolet tipped over.
It made for an interestingafternoon's entertainment for Manchester United manager Sir AlexFerguson, who was watching from the stands and will pit his sideagainst City in the FA Cup semi-final at Wembley later this month.
?PREMIER LEAGUE LIVE: The action from Manchester City v Sunderland s it happenedManchester City would be 'crazy' to sack me now says boss Mancini Manchester City to fight Ireland's ?1.5m claim for pay-offManchester City FC news, features and opinion Sunderland FC news, features and opinion
?Explore more:People: Carlos Tevez, Patrick Vieira, David Silva, Steve Bruce, Adam Johnson
Source: Daily Mail
Source: Daily Mail