City scored first when Raheem Sterling finished off a superb team move and Fernandinho headed in a second from Kevin de Bruyne’s free-kick.
West Ham pulled a goal back in the second half when Michail Antonio nodded in Arthur Masuaku’s cross.
Sterling added his second late on when he stroked home from a tight angle.
Relive City’s 3-1 win over West Ham
The season may be in its infancy but already the title contenders have put down a few markers with three games gone.
Chelsea and Manchester United both secured victories on Saturday, which turned the focus on Pep Guardiola’s side before the international break, and they responded with a determined display.
A blistering start – underpinned by the attacking triumvirate of Sterling, Sergio Aguero and Nolito – yielded a slick goal finished off by Sterling.
It was not just the polished passing and intense pressing which caught the eye. City’s second goal ensured four of their nine Premier League goals this season have come from set-pieces.
That they could not convert their first-half dominance into more goals will be mildly concerning to Guardiola as they allowed West Ham back into the contest after the break.
However, a steely response to see out the victory when put under pressure, before Sterling calmly passed the ball into the net in injury time, will have pleased the City boss.
Rejuvenated Sterling proving his worth
Last season Sterling did little to justify the £49m City paid Liverpool for him in July 2015, while Euro 2016 with England proved to be a nadir in a difficult 12 months.
Inevitably it led to questions about whether his burgeoning talent would ever be realised at City, and more pertinently in the short term whether he would feature in Guardiola’s immediate plans.
The Catalan’s ruthless streak – as goalkeeper Joe Hart and midfielder Yaya Toure are finding out – has come to the fore early in his tenure.
Sterling, though, has been rejuvenated by Guardiola and his two goals put the gloss on another impressive display.
With three assists so far in this campaign, he has had a hand in five goals in four games.
By contrast, he was involved in just four goals in his last 17 appearances under Guardiola’s predecessor Manuel Pellegrini.
If Sterling’s form can be sustained over the course of the 2016-17 season, he will emerge as a key component in City’s quest for silverware.
Gritty West Ham lacking cutting edge
There was every chance Slaven Bilic’s side could have been blown away by City, such was the home side’s imperious start, but they stood firm.
It was a spirited showing from the visitors, particularly after their disappointing exit from the Europa League on Thursday, and the Etihad crowd shifted uneasily once Antonio pulled a goal back.
Had the Hammers possessed a more potent goal threat they may well have left Manchester with more to show for their efforts.
Enner Valencia and Ashley Fletcher showed plenty of willing but the lack of cutting edge emphasised why Bilic has brought in Italy striker Simone Zazafrom Juventus on a season-long loan.
With only a few days left before the transfer window closes, Bilic may yet feel the desire to strengthen his goalscoring options further.
Will Aguero be suspended for the Manchester derby?
The only sour point for Guardiola will be the prospect of a possible suspension for Aguero for the Manchester derby on 10 September.
Aguero lashed out with an elbow on Winston Reid which caught the West Ham defender in the throat. The incident was missed by referee Andre Marriner while neither manager claimed to have seen it.
BBC Radio 5 live pundit Robbie Savage believes the Argentina forward may be handed a retrospective ban when the Football Association reviews the video evidence.
“The replays don’t look good. I think he’s going to be in trouble,” Savage said.
“Only Aguero knows if he’s elbowed Winston Reid. I can’t say he’s done it on purpose but on the replays it looks like he swung his arm back and caught him in the throat.”
Man of the match – David Silva (Manchester City)
What they said:
Manchester City manager Pep Guardiola: “At 2-1, the emotions, not the tactics, went in. We created many chances, I don’t know how many shots we had but the performance in general was real good with or without the ball. With the quality of our players, we can be satisfied.”