Gabriel Jesus opened the scoring on Saturday, Sterling scored twice and Sergio Aguero netted a penalty before Sterling rounded things off with the fifth as City picked up where they left off last season.

Sheffield United picked up a point on their return to the top-flight with a 1-1 draw at Bournemouth while Burnley and Brighton both claimed opening-weekend victories.

City started slowly at West Ham but three goals in the last 15 minutes sealed a convincing start to their title defence.

"Overall for the first game it is an incredible result," City manager Pep Guardiola said.

"The first half was not good. We didn't control second balls and lost a lot of balls. Second half was much better. More calm, but still we have many things to improve."

West Ham had a couple of half-chances before Jesus scored the opener on 25 minutes and Sterling made it 2-0 just after half-time.

Sterling then had a goal ruled out by VAR - video assisted referee - for offside but the England striker made amends with his second goal on 75 minutes.

VAR was then used again when Aguero saw his penalty saved by Lukasz Fabianski but the kick had to be retaken because Declan Rice had encroached in the penalty area and made the resultant clearance.

Aguero made no mistake second time round and Sterling rounded off things with the fifth as City scored three late on.

Guardiola said VAR would be a test for all sides this season as it is used in the Premier League for the first time.

"You have to be mentally strong when VAR is not on our side," he said.

"You think at 0-3 the game is almost over but at 0-2, the game is completely different, you have to be calm and be strong.

"It is going to change the dynamic not just for the team but for the spectators. It will be a good lesson for our future."

West Ham manager Manuel Pellegrini said his side did not deserve to lose by five goals.

"I don't think the score reflected the difference between the two teams," he said.

Billy Sharp scored an 88th-minute equalizer to give Sheffield United a 1-1 draw at Bournemouth in their return to the Premier League for the first time since 2007.

Chris Mepham had put Bournemouth in front just after an hour before Sharp pounced to score the equalizer two minutes from time.

Ashley Barnes scored twice and Johann Gudmundsson got the other as Burnley beat Southampton 3-0 in rainy, windy conditions.

Brighton won 3-0 at Watford thanks to Abdoulaye Doucoure's own goal and strikes from Florin Andone and Neal Maupay.

Morgan Schneiderlin was sent off 12 minutes from time but Everton held on with 10 men for a 0-0 draw at Crystal Palace.

Tottenham play Aston Villa in the day's late match, while Liverpool beat Norwich 4-1 Friday in the season-opener.

Australian Associated Press