Story of the Match
With 129 league goals between the two sides so far this season, there was a sense that we could be in for a goal fest at the Etihad Stadium, and it didn't take long for the ball to hit the back of the net, as highly-rated youngster Fabio Carvalho gave the visitors a dream start.
A hopeful cross field ball to Harry Wilson was brought down exquisitely by the Welsh youngster, who made light work of Joao Cancelo before wrapping the ball around the outside of the foot to allow the arriving Carvalho to tap home from inside the six yard box, sparking rapturous scenes amongst the 3,000 travelling Fulham fans.
The joy was short lived for the Fulham fans though as the hosts hit back 90 seconds later. Mahrez, playing in his first game since returning from the African Cup of Nations was heavily involved in the build up before pulling the ball back for Gundogan to fire home from 12 yards.
Fulham were not deterred by City's equaliser, and continued to probe in a manner similar to the one that has seen them open up a five point lead at the top of the Championship, with top scorer Aleksandar Mitrovic firing wide from distance.
A high scoring affair looked almost certain after a frantic opening 15 minutes, but that was about as good as it got in the first half, with the hosts dictating the run of play without really testing the form of Paulo Gazzaniga.
City continued their dominance in the second period, and soon found themselves two goals to the good as Mahrez fired home from the penalty spot after Jack Grealish had been brought down by Joe Byran.
Three became four soon after, as Kevin De Bruyne nicked the ball away from Fulham before selflessly laying the ball off to the arriving Mahrez. The Algerian made no mistake in firing home his second of the afternoon to all but confirm City's progress into Round Five.
Delap, who has been out of action for the last six months, looked to have secured the dream return to the first team fold as he headed home at the back post. The offside flag went up though, and VAR confirmed that the youngster was indeed offside.
Full-time: Manchester City 4-1 Fulham.