The Hammers’ problems at their new home continued on Friday as they were torn apart by a rampant Citizen’s team, the visitors going 3-0 up in the first half.
Two further strikes after the break were a fair reflection on City’s dominance of the third round tie as Slaven Bilic’s isde threw in the towel on another night to forget for the Croat and his team at the London Stadium.
Surprisingly, West Ham had started well and threatened to make it a tough night for City for half an hour, Michail Antonio’s shot well saved by Willy Caballero.
The visitors always looked sharp when they got into the right areas though, Sergio Aguero seeing his effort tipped over well by Adrian.
There was an element of controversy about the opener in the 33rd minute when Angelo Ogbonna was adjudged to have up ended Pablo Zabaleta in the box, referee Michael Oliver having no hesitation in pointing to the spot.
Yaya Toure emphatically dispatched the penalty to take him to 13 from 13 for City from 12 yards.
West Ham had a chance to level the scores immediately when Antonio’s shot fell into the path of Sofiane Feghouli but he put his effort wide with the net at his mercy.
City punished the Hammers for Feghouli’s miss just minutes later, putting together a great move down the right before Havard Nordtveit put Bacary Sagna’s cross into his own net as he attempted to stop Raheem Sterling scoring.
The tie was over just two minutes before half-time when David Silva added a third, the visitors cutting West Ham’s defence to ribbons before Silva slotted home.
There was to be no let up from City after the break, Sergio Aguero grabbing the fourth five minutes after the interval when he flicked Toure’s effort over Adrian for his 18th of the season.
The home side had long since thrown in the towel and the only surprise was that City did not score more before John Stones opened his account for the club in the 84th, heading home from a corner to put the exclamation point on the Citizens' progression to the fourth round.