Aaron Cresswell had made the scoreline more respectable at the break before Gabriel Jesus restored City's two-goal lead seven minutes after, opening the floodgates against West Ham's defence.
The champions would find their fourth on the 64th minute. Fernandinho sent team-mate Raheem Sterling down the right wing who returned the favour by setting up the Brazilian on the edge of the box.
The City utility man was in tonnes of space and had no trouble finding the back of the net with a placed finish to make it 4-1 at the London Stadium.
Check out the goal for yourself:
April 29, 2018