Even on those rare occasions when it seems they might be at risk of slipping up, Manchester City can always draw strength from the likelihood of Erling Haaland producing the unanswerable ruthlessness that made the difference in this victory over an insubordinate West Ham.

Be afraid. After falling below peak sharpness at the end of last season, Haaland is back to his awesome best and is making defenders tremble again. Another hat-trick to follow on from last week’s destruction of Ipswich brought the striker to seven goals in his first three games and ensured that City, who lived dangerously at times, maintained their perfect start on an evening when West Ham saw signs that Julen Lopetegui’s attempts to play a more expansive style will bear fruit in the long run.

Ultimately West Ham’s calculation was to decide between suffering without the ball for the 90 minutes and the adventure of seeing where having a go at the champions would take them. In opting for the latter, they kept the crowd engaged throughout and had hope of snatching a point before Haaland surged through to kill the contest with a chipped finish in the dying stages.

It was worth the gamble. Mohammed Kudus and Tomas Soucek had chances to make it 2-2 during an even second half, although the inevitable cost to West Ham’s lack of caution was the space that Bernardo Silva, Kevin De Bruyne and a rejuvenated Jack Grealish had to keep linking with Haaland.

Afterwards Pep Guardiola spoke with a satisfied air, not least because City had punished Arsenal’s draw with Brighton earlier in the day. The manager praised West Ham, who contributed to the entertainment levels both through their attacking play and their curious reluctance to have anyone marking Haaland.

Six minutes in, with City relieved not to be behind after Ederson saved from Jarrod Bowen and Josko Gvardiol denied Michail Antonio a tap-in, there was a warning when an unchallenged Haaland headed over after a clever combination between Silva and Grealish on the left.

The visitors led four minutes later. West Ham had just about survived another raid from De Bruyne when Lucas Paquetá lost track of Emerson Palmieri’s heavy pass just outside the area, inviting Silva to nip in and send Haaland through to roll a disdainful finish past Alphonse Areola. “This kind of gift, this team doesn’t forgive you,” Lopetegui said. “Then we suffered.”

City spent the next few minutes threatening to humiliate West Ham. Grealish, starting for the first time since April and in a sprightly mood after his England recall, shot wide. Areola saved an audacious effort from De Bruyne, who would soon see another shot crash off the woodwork.

Relieved only to be 1-0 down, West Ham hit back out of nothing. Bowen darted down the right, skipped past Gvardiol and delivered a low cross that was probably not going to lead to anything until Rúben Dias turned it past Ederson for a needless own goal.

It was a rare loss of composure from City. Mateo Kovacic kept threading passes through West Ham’s midfield pivot of Edson Álvarez and Guido Rodríguez, who did not know how to handle the constant movement around them. A second goal arrived after another slick move on the half hour. Grealish moved away from Aaron Wan-Bissaka before a neat exchange between Silva, Kovacic and Rico Lewis left Haaland in space on the right. With Emerson slow to react, the striker walloped a rocket past Areola.

Somehow West Ham clung on, defending with enough heart to give themselves a chance. Kudus might have scored before half-time and the winger looked certain to equalise in the 52nd minute, only to strike a post after latching on to Bowen’s brilliant pass. There was a shift in the mood, a sense that West Ham had renewed belief. Ederson flew out of his area to head a ball away and Bowen saw a shot blocked. Grealish flickered again, teeing up Silva to shoot straight at Lukasz Fabianski, who had replaced the injured Areola at half time.

Needing more control, Guardiola introduced Ilkay Gündogan for Jérémy Doku and Matheus Nunes for Grealish. West Ham responded with Niclas Füllkrug and Soucek, who would slice a decent chance wide.

Against lesser opponents West Ham might have left with more. A second consecutive home defeat in the league felt easier to take given that it came courtesy of City’s goal machine. West Ham pushed forward, only to be caught out when Nunes skipped through a tiring midfield and sent Haaland through to do what he does best.