Raheem Sterling scored a hat-trick as Manchester City got their title defence off to a winning start with victory at West Ham in game that saw the video assistant referee play a significant role for the first time in the Premier League.

The technology is making its debut in England's top flight this season and, after last night's curtain raiser between Liverpool and Norwich passed off without incident, it took centre-stage on Saturday.

VAR was first called on when Gabriel Jesus appeared to have put City 3-0 up midway through the second half, only for Raheem Sterling to be ruled fractionally offside in the build-up.

After Sterling added City's third, a moment also reviewed for possible offside, the system then awarded the visitors a penalty retake after Sergio Aguero's tame effort was saved by Lukas Fabianski but Declan Rice was deemed to have encroached into the area. The striker made no mistake at the second attempt.

VAR: How will the Premier League adapt?
This was, nevertheless, a dominant and deserved victory for Pep Guardiola's side, who laid down a marker for the season ahead in emphatic fashion.

The visitors had looked a little short of their best early on but they took the lead midway through the first half when Jesus flicked in Kyle Walker's low ball into the box.

They doubled their advantage six minutes into the second half, Sterling sliding in a low shot after being put through by Kevin de Bruyne.

After Jesus' VAR-denied effort, a third did come for City as Sterling ran on to a ball over the defence before coolly lobbing Fabianski. And after Aguero's retaken penalty, Sterling got his third in injury time to complete the rout.
City pick up where they left off

City struck the first blow against Liverpool by winning the Community Shield last weekend, only for the Reds to respond with an impressive 4-1 thumping of Norwich in the league on Friday night.

And a few eyebrows were raised as City made a lethargic start in London, perhaps caught off-guard an aggressive start from the hosts. Ultimately though - as so often last season - it proved a false dawn and the visitors eventually took full control.

Improve this City side is no mean feat but Guardiola's summer signings look like good additions to an already hugely talented squad. Rodri, the club's £63m record signing from Atletico Madrid, slotted straight into midfield and impressed with his physicality and eye for a pass.

And even if full-back Joao Cancelo did not start, he still appeared to have had a positive impact on the team - Walker appeared especially keen to impose himself on the game and turned in an impressive performance, including the assis for the opener.

Games between these two sides have been heavily one-sided affairs in recent seasons, with City having now won their past eight competitive matches against the Hammers, scoring 28 goals and conceding just four in the process.

On this evidence, the champions are going to take some stopping.
Hope for Hammers despite big defeat

West Ham have struggled to get comfortable at London Stadium since moving in three years ago but former City boss Manuel Pellegrini appears to have steadied the ship since arriving last year - and after a summer in which they look to have recruited well, there is a real sense of optimism among fans that their side can challenge for the top six.

Sebastien Haller and Pablo Fornals have come in for a combined £69m, adding additional flair to an attack that includes Manuel Lanzini and Felipe Anderson.

Haller, who scored 14 goals in 27 appearances for Eintracht Frankfurt last season, immediately looked a more than capable replacement for Marko Arnautovic, who moved to China in the summer.

His excellent hold-up play and ability to bring in others was a big factor in the Hammers dominating their opponents in the opening 20 minutes.

West Ham have not had a 20-goal-a-season striker since Teddy Sheringham back in 2004-05. Whether Haller can hit that target this season only time will tell, but his all-round play means he looks set to be a useful acquisition.

So while this was another heavy defeat for West Ham against City, it is not a game on which their prospects for the coming season can be fairly judged.