CNN  — 

Any doubts that Manchester City was the favorite to defend its Premier League crown were quickly extinguished at the London Stadium Saturday.

A Raheem Sterling hat-trick helped Pep Guardiola’s side cruise past West Ham 5-0, which means City has now won its season opener for nine consecutive years.

The emphatic scoreline bettered rival Liverpool’s 4-1 victory over Norwich City on Friday night, further evidence that these two sides will be frontrunners again this season.

It was also an action-packed afternoon for the video assistant referee, which is being used in the Premier League for the first time.

The system was called into action on a number of occasions – once to rule out a score for Gabriel Jesus, once to allow a Sterling goal to stand, and once to let Sergio Aguero atone for a missed penalty in the second half.

“It’s a bit difficult during the game because you want your goal to stand,” Sterling, who recorded his third Premier League hat-trick, told BT Sport after the game. “But at the end of the day, if the decision’s right, that’s all that matters.”

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Raheem Sterling takes the match ball after scoring a hat-trick.

Both sides had chances in the game’s opening stages, but it was City that stole the advantage at 24 minutes when a surge of pace allowed Kyle Walker to get behind the West Ham defense.

The Englishman crossed into the path of Gabriel Jesus, who opened City’s account for the new season by clipping his shot past Lukasz Fabianski.

Sterling performance – by Sterling

Sterling got his first at the start of the second half when he was put into space by Kevin De Bruyne, and from then on, things turned sour for West Ham.

Jesus almost grabbed his second just two minutes later, but VAR adjudged the Brazilian to have stepped offside by the slimmest of margins.

READ: Liverpool opens title campaign with comfortable win

Sterling, who also plays for England’s national team, scored his second after Riyad Mahrez chipped over the Hammers’ defense, VAR this time ruling in City’s favor.

Mahrez helped set up the fourth when he was brought down by Issa Diop in the penalty area.

Man City icon Shaun Wright-Phillips talks family, racism within football & Mourinho_00002511.jpg
Man City icon Shaun Wright-Phillips talks family, racism within football & Mourinho
04:03 - Source: CNN

Aguero’s low attempt was saved by Fabianski, but VAR intervened, ruling that the goalkeeper had stepped off his line too early, allowing the Argentine to retake.

He made no mistake the second time, firing into the bottom-left corner of Fabianski’s goal.

Sterling’s third and City’s fifth came in stoppage time – the icing on the cake for the defending champion.

“It was quite difficult in the first half to get the cobwebs off,” said Sterling. “The breathing was heavy, some of the touches were heavy, but once the team got into a rhythm, you can find the passes easier.

“Once that second goal went in, things went a lot smoother and a lot more chances came.”

Referee Mike Dean consults the video assistant referee

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VAR takes center stage

After a quiet opening night at Anfield, VAR was given its first real Premier League test in east London having already been integrated into major football competitions around the world.

City’s dominance ensured that video replays were never going to decide the result of this game, and Guardiola said afterwards that his team had learned to come to terms with the system after last season’s Champions League quarterfinal defeat by Tottenham.

“It’s good mentally because you are thinking 3-0, the game is over, okay, and then immediately it’s 2-0 and [West Ham] have an incredible chance and you can go to 2-1 [with] 15 minutes left.

“You have to be strong, calm and positive. We have to learn to control our emotions.”

Man City players celebrate Sterling's second goals against West Ham.

As for West Ham, a series of strong summer signings meant there was plenty of optimism around the club heading into the new season, most notably with the acquisition of French forward Sebastien Haller.

Despite a bright start, the Hammers’ only real chance came midway through the second half when Ederson was forced to make a brilliant double save to deny Javier Hernandez and Manuel Lanzini.

The result means West Ham has lost by at least four goals in its last three season openers.

On Saturday, however, it faced probably the toughest opponent it will all year.