Goals from Leroy Sane, Fernandinho and Raheem Sterling at The Hawthorns ensured Pep Guardiola's unbeaten side took their tally of points to 28 out of a possible 30 after 10 games.
That equalled the best return at this stage of a season in the Premier League era, matching the performances of Chelsea in 2005 and City themselves in 2011.
Both those sides went on to win the title but neither started with quite the swagger of Guardiola's charges, who have scored 35 league goals with a goal difference of plus-29.
The scoreline ultimately flattered Albion who were largely outplayed from the moment Sane put City ahead after 10 minutes with a left-foot shot into the corner - his eighth goal of the campaign.
West Brom did equalise within two minutes when Jay Rodriguez got in behind the defence but City reasserted control in the 15th minute through Fernandinho after the Brazilian's 30-metre shot took two deflections before hitting the post and rolling into the net.
As City continued to dominate, substitute Sterling added the third 10 minutes after coming on midway through the second half, tapping in from close range after a cross from Kyle Walker at the end of a patient move.
Matt Phillips did snatch a 92nd-minute consolation for West Brom following a mistake by Nicolas Otamendi, who chested the ball back towards goal without seeing the striker, but it could not camouflage City's obvious supremacy.
Arsenal came from behind to beat Swansea City 2-1 as second-half goals from Sead Kolasinac and Aaron Ramsey saw off the injury- weakened visitors.
The visitors, without injured striker Wilfried Bony, midfielder Renato Sanches and defender Martin Olsson, took the lead in the 22nd minute against the run of play. Sam Clucas ran on to a pass from Tammy Abraham and slotted the ball neatly beneath Arsenal goalkeeper Petr Cech.
Arsenal's powerful Bosnian left back Kolasinac equalised in the 51st minute and set up Ramsey to put the home side ahead in the 58th with his third goal of the season.
Kolasinac came off with a slight hip injury in the 78th minute, but Wenger is hoping he will be able travel with the squad to league leaders Manchester City.
"We hope to get him fit for next Sunday. He had that before, and we managed to get him always available," Wenger said.
Liverpool breezed past Huddersfield Town 3-0 with Daniel Sturridge's goal setting up the victory.
Mohamed Salah had a first-half penalty saved but that was largely forgotten by the end as Juergen Klopp's side produced a vibrant second-half display with Roberto Firmino and Georginio Wijnaldum on target after Sturridge broke the deadlock.
Their first win in four league games kept Liverpool in touch with the top four, moving them up to sixth spot with 16 points from 10 games, three behind fourth- placed Arsenal.
Liverpool's home form contrasts sharply with their away results and they have now conceded only once at Anfield compared to the 15 they have let in on their travels - the most recent setback being last week's 4-1 loss at Tottenham Hotspur.
Huddersfield are also finding it tough on their travels and rarely worried Liverpool's defence.
They defended resolutely, though, and reached the interval at 0-0 thanks to Jonas Lossl's save to stop Salah's spot-kick.
Sturridge eased any home anxiety in the 50th minute when Huddersfield defender Tommy Smith's misguided header fell into his path and he dinked in his first goal since August.
Eight minutes later Firminho met James Milner's corner with a firm header to make it 2-0 and Wijnaldum smashed home the third as Huddersfield's resistance crumbled.
David Wagner's side managed only one goal attempt and they have now failed to score away since they began the season with a 3-0 victory away at Crystal Palace.
Eden Hazard scored the only goal as Chelsea ground out a 1-0 victory over Bournemouth and kept their spot in the top four.
The Belgium winger beat Bournemouth goalkeeper Asmir Begovic at his near post shortly after halftime, and Chelsea moved back within a point of third-placed Tottenham.
Alvaro Morata thought he gave Chelsea the lead as he tapped-in from close range before looking up to see the offside flag raised, in what was a marginal call against Cesar Azpilicueta.
Morata was denied again five minutes later, this time by Begovic, the former Chelsea stopper.
It was little surprise Morata was involved when Chelsea finally broke the deadlock, although some comical defending from the home side helped.
Simon Francis failed to intercept Morata's ball over the top before Begovic was left looking sheepish after letting Hazard's effort sneak in at the near post.
Bournemouth came close but Jordan Ibe's effort was deflected over the bar by Rudiger, who justified his selection.
Elsewhere, Stoke secured a much-needed three points by beating Watford 1-0, and West Ham drew 2-2 with Crystal Palace after Wilfried Zaha equalised in the dying seconds.
