Coming into the contest on the back of a disappointing defeat to Real Madrid in midweek, Pep Guardiola’s side looked determined to find a positive response against Newcastle.
The hosts came flying out the blocks and their fast start was rewarded with a breakthrough in the 19th minute when Ederson’s hopeful long ball released Marmoush through on goal, and the Egyptian held his nerve to lift a sublime lob over Martin Dubravka for his first goal in City colours.
Armed with all the momentum, City doubled their lead just five minutes later as Marmoush swept a low finish beyond Dubravka from 18 yards after good work by İlkay Gundogan.
Having won six straight games on the road, Eddie Howe’s men searched for a route back into the match after a dismal opening half-hour, but it was the rampant Cityzens who extended their advantage before half-time.
Savinho showed impressive vision to pick out Marmoush in the box, and the forward powered a clinical first-time effort into the corner to complete a remarkable first-half hat-trick.
City continued to stamp their authority on proceedings at the start of the second half, with Dubravka called into action to thwart Savinho and Erling Haaland in quick succession.
The visitors refused to lie down without a fight, however, and Ederson had to be alert to parry a swerving strike from Lewis Miley as Newcastle probed for a moment of quality in the final third heading into the closing stages.
Clear-cut chances came at a premium for the Magpies though, and the hosts added a fourth with six minutes remaining when substitute James McAtee volleyed home from Haaland’s flicked header to put the seal on a perfect afternoon for Guardiola’s side.
It’s a first clean sheet in seven for City, who rise to fourth in the PL table, while Newcastle suffer a third defeat in four league matches, losing valuable ground in the race for UEFA Champions League qualification.