City and boss Guardiola were without a win in six matches in all competitions, but Sergio Aguero flashed in Ilkay Gundogan's through ball to give them the lead.

The Baggies were flat and Aguero struck again, punishing hesitant defending with a powerful, top-corner finish.

West Brom improved hugely after the break but failed to take their chances before Gundogan twice slotted home - first from Aguero's chip and then after being found by Kevin de Bruyne.

The win means City leapfrog Arsenal, who won 4-1 at Sunderland earlier in the day, into first place in the table with 10 matches played.

Tony Pulis' side struck the post through Gareth McAuley late on and should have got one back at 2-0 through Salomon Rondon, but they slip to 15th and are now without a win in their past five games.

Sergio is back

Aguero's last goals for City came in the 3-1 league victory at Swansea on 24 September, which was also City's most recent win before today. Who better, then, to set the tone at the Hawthorns?

The Argentina striker's first was rifled in brilliantly after his clever run was matched by Gundogan's quality pass into the space between West Brom's two centre-backs.

His second was spectacular, but equally simple. McAuley and Jonas Olsson both should have cleared a loose ball on the edge of the box but hesitated, allowing the 28-year-old to set himself up and smash home.

That was his seventh league goal of the season - the joint best return with Chelsea's Diego Costa - and ends a spell of six matches without a goal.
But don't forget Gundogan

West Brom's players were obviously deflated by Aguero's two goals in nine minutes, so Pulis deserves credit for managing to galvanise his side into producing a spirited second-half display.

They might have got themselves back in it when Rondon miscued his finish when meeting James McClean's excellent cross, and Claudio Bravo almost gifted the Venezuela striker a goal when he rashly came to clear and left his goal exposed, but Rondon's header bounced just wide.

But City managed to ride out the pressure and always looked dangerous on the break, with Aguero hugely influential in driving forward on the counter-attack.

He was in search of the hat-trick, but it was Gundogan who expertly slid the ball past Ben Foster to end the Baggies' revival - meeting Aguero's fantastic dinked pass through the back line.

The 26-year-old Germany midfielder was excellent throughout, and his first-time finish for City's fourth capped his best performance since joining from Borussia Dortmund this summer.
Man of the match - Sergio Aguero (Manchester City)

What they said

Manchester City manager Pep Guardiola: "When we lose there are always doubts. Also in the second half I had doubts when we didn't play too well.

"I had doubts and saw what we had to improve. It's the first time I have not won in six games. Always you have doubts. Not over the principles.

"We need Sergio. We know how important he is for us when he can convince us how good he is and how important he is for this club.

"I am going to help him to be much, much better. That is my target.

"I'm so, so happy for him because with all of that he is one of the nicest people I have met.

"He is part of the history for this club. He is one of the best."

West Brom manager Tony Pulis: "In the first half we sat back waiting for it to happen. In the second half we gave it a go but needed to score. As the game opens up they have real quality on the break.

"I'm disappointed with all the goals. We should do better. You look at the money they have spent and their quality and depth is absolutely frightening."

Stats of the day

    West Brom have lost their past 10 Premier League games against Manchester City, conceding 28 goals in the process.
    Sergio Aguero has scored seven times in nine league games against West Brom.
    Aguero has also scored six goals in his past four Premier League away games.
    City have kept a clean sheet in eight of their past 13 league meetings with West Brom, and conceded just one goal in the past four meetings.
    The Baggies have had just two shots on target in their past 180 minutes of action in the Premier League.

What's next?

Manchester City's next game is at home to Barcelona in the Champions League on Tuesday (19:45 GMT kick-off). They next play in the league at home to Middlesbrough in a 15:00 kick-off on Saturday.

West Brom's next match is away to Leicester in a 16:30 kick-off in the Premier League on 6 November.