After being away with Egypt at the Africa Cup of Nations, Marmoush returned last week and featured off the bench in our Champions League defeat to Bodo/Glimt, but Pep Guardiola opted to start the forward this time around at the Etihad Stadium, and he swiftly repaid the faith of his boss.
Matheus Nunes whipped in a superb cross from the right flank and Marmoush showed hunger and desire to charge in front of the defender to poke us ahead after just six minutes.
The Egyptian was a constant threat and almost doubled our lead before the interval, seeing his shot crash off the post, as a potential penalty for a handball in the build up to the chance was waved away following an onfield review by the referee.
Deep into first-half stoppage time, we doubled our lead from a fine Antoine Semenyo finish for his third City goal in four appearances since making the move to Manchester earlier this month.
The visitors showed determination after the interval and almost pulled a goal back shortly before the hour mark, but Joao Gomes struck over the bar.
Semenyo then came close to grabbing a brace with 15 minutes left to play, but his ferocious left-footed strike crashed off the crossbar from 18 yards.
We remained professional to return to winning ways after three successive games without a victory, taking us four points behind Arsenal who are yet to play this weekend.
View the best images from the victory via our gallery below.