Gabriel Jesus was the first ‘victim’ of a video assistant referee-assisted decision in the Premier League.
The Brazilian forward, 22, thought he had slotted home his second goal of the game - and Manchester City’s third - when he tapped into an empty net in the second half.
But after a short delay, VAR replays showed the initial pass from Kevin de Bruyne to Raheem Sterling found the latter marginally offside.
West Ham fans were left jubilant as the goal was chalked off - having suddenly found themselves three goals down in their season opener.
Fans of the Manchester club, though, were left frustrated as replays at first glance appeared to be tight, despite having a two-goal lead at the time thanks to Jesus and Sterling.
Replays also validated Sterling’s strike later in the match, but it was the penalty kick won by Riyad Mahrez which caused greater controversy.
Substitute Sergio Aguero saw his spot-kick saved by goalkeeper Lukasz Fabianski, but a re-take was ordered as the West Ham man was found to be off his line.
The Argentina forward converted the second attempt which left home fans frustrated en-route to a 5-0 home defeat.
It is the first game week - and only the second match - in which video assistants can help Premier League referees make decisions, with clubs ruling to introduce it in 2018.
The first, Liverpool’s 4-1 thrashing of newly-promoted Norwich, saw the new system make it’s debut - but not without a blip.
Although VAR was not required to make any major decisions - all goals were checked and confirmed as valid - a technical flaw saw the start to the second half delayed.
How does VAR work in the Premier League?
Match referees in England will be able to review decisions in four ‘game-changing’ instances.
That includes where goals, penalty kicks and red cards are awarded - as well as cases of mistaken identity.
VAR can also alert the referee to an off-the-ball incident which he may have missed, which could result in a dismissal.
There are some differences to how it will work in the Premier League - compared to UEFA competitions and the men’s 2018 World Cup.
One of those major differences is that referees will not have to view the pitch-side monitor for a replay; those in the VAR studio will make the call and the referee will generally accept it.
That monitor can, though, be used where an off-the-ball incident is brought to his attention.
Cutting out the use of the monitor is said to be able to save approximately 90 seconds per decision, which should help mitigate some fans’ fears.
‘You can’t celebrate anymore’
The decisions added to some fans’ fears that replays will slow the game down, with the officials taking minutes to make the right calls.
One user posted on Twitter fears that they could not even celebrate goals any more, for fear they would eventually be overturned.
Another fan, similar enraged, argued the technology has ‘ruined football’.
But there is still plenty of time for VAR to win over its critics as the system seeks to eradicate referee errors in the top flight.
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