The visitors took the lead after just three minutes when Alvaro Negredo was left completely unmarked in the box to nod home a cross from close range.
Negredo capped off the scoring in the second half, driving into the area before sliding in and chipping the keeper for his fifth goal of the tie.
Here Sports Mole takes an in-depth look at a comfortable evening for City in London.
On target: 3
On target: 6
Was the result fair?
The stats make the match look very even, but what they don't account for is the fact that Man City rarely moved out of second gear. They were comfortable for the whole match and, as soon as Negredo scored in the third minute, there was only going to be one winner.
West Ham did show glimpses of threatening but they did nowhere near enough to warrant anything out of this match. The tie was over as a contest before kickoff, and the match pretty much followed suit after the early goal.
West Ham's performance
It is hard to evaluate West Ham's performance in this match as it was something of a dead rubber. The hosts approached it as more of a high-profile friendly, knowing that they had no chance of progressing to the final after their first leg defeat.
Still, there were positives to take out of the game for Sam Allardyce, most notably Andy Carroll's first-half performance as he continues his journey back to full fitness. The England striker was a handful up front and was the Hammers' best player until he was taken off at the break.
The defending will have angered Allardyce, but perhaps the worst thing to happen in this match was an injury to Mohamed Diame, who was forced off late with a knee injury.
Man City's performance
It was a professional performance from City tonight. They did 99% of the job in the first leg and made sure that the final piece was applied comfortably this evening, cruising to the victory.
City never looked like they were in trouble but, even if West Ham did threaten, you sensed that Manuel Pellegrini's side had a lot more to give in the match. They dictated the tempo of the game and were in complete control from start to finish.
With a crowded fixture schedule coming up, such an easy match will have been a big plus for City. Pellegrini also had the chance to field the returning Stevan Jovetic and Jack Rodwell as subs, while Sergio Aguero continued his goalscoring return from injury.
Sports Mole's man of the match
Alvaro Negredo: 'The Beast' just can't stop scoring at the moment. He bagged another brace this evening and is proving to be just as important to City as his strike partner Aguero.
His first goal was, quite frankly, a gift as he was left free inside the box for a simple finish, but the second goal was a very impressive piece of play from the Spaniard. He showed good strength and pace to burst into the box past two players before producing a lovely little finish over Jaaskelainen on the slide when it looked like the chance had gone.
This has to be the defending for the first Negredo goal. James Tomkins was sucked into no man's land, caught between deciding who to mark having been left with two players. Razvan Rat failed to come in from left-back on the cover, and as a result Negredo had far too much room in the area to nod past Jaaskelainen. The Spaniard has scored plenty of goals this season, but few will have come quite as easy as that.
This was never going to be the toughest game for Chris Foy to referee, with both sides treating it almost like a training match. There were two notable penalty shouts for West Ham in the second half, both of which may have been given on another day but, being so far behind, the appeals were not too loud from the hosts.
West Ham: Things don't get an easier for the Hammers as they travel to Stamford Bridge to take on Chelsea next Wednesday.
Man City: City, meanwhile, will continue their quest for the quadruple when they host Watford in the FA Cup on Saturday.