Phil Foden registered twice, while Julian Alvarez, Oscar Bobb and Jeremy Doku were also on the scoresheet, with the Citizens proving to be far too strong for their Championship opponents on the afternoon.
Man City will naturally be the favourites to defend their crown this season, and head coach Pep Guardiola demonstrated that he will be taking the competition seriously by naming a strong side.
Kevin De Bruyne made his return from a long-term hamstring injury in the second period, and he set up Doku for Man City's fifth of the contest in the 74th minute.
Leeds United have also advanced to the next stage of the competition, with Ethan Ampadu scoring twice, while Patrick Bamford also registered, as the Whites won 3-0 at Peterborough United.
West Bromwich Albion were also big winners on the afternoon against National League outfit Aldershot Town, finding the back of the net on four occasions.
Nathaniel Chalobah, Jovan Malcolm, Daryl Dike and Tom Fellows were on the scoresheet in a 4-1 success, with Lorent Tolaj registering a consolation for the visitors in the final exchanges.
There was no winner between Luton Town and Bolton Wanderers, though, with the two teams playing out a goalless draw, so a replay will be required to determine which side advances to the next stage.
There was also a draw at the City Ground between Nottingham Forest and Blackpool, with a 2-2 meaning that the two sides will lock horns in a replay for a position in the fourth round.
Wrexham have advanced, with the Welsh outfit claiming a League One scalp in the shape of Shrewsbury Town, with Thomas O'Connor hitting the winner in the 72nd minute of the contest.
West Ham United were the favourites to overcome Bristol City in the third round of the contest at the London Stadium.
However, the Hammers were held to a 1-1 draw by the Championship outfit; Jarrod Bowen sent David Moyes's side in the fourth minute of the contest, before Tommy Conway levelled the scores in the 61st minute.