Fans have questioned whether the ball was in ball before Japan's winning goal against Spain.
Ao Tanaka scored from close range as Japan came from behind to lead against their European opponents.
The goal was initially disallowed with the ball appearing to have gone out of play before Kaoru Mitoma's cross into the box.
A long VAR check followed with Tanaka eventually awarded the goal, after it was ruled that the whole ball had not crossed the line.
'That dead ball line is going to be a part of Japanese football history as things stand,' ITV commentator Clive Tyldesley said.
'I need another look at that one Clive', co-commentator Ally McCoist said, prompting Tyldesley to quip 'Oh I think we'll be seeing it again.'
Fans on social media also questioned the decision to award the goal.
'How's that second Japan goal stood,' one fan said on Twitter. 'VAR is a great laugh.'
A second fan claimed 'Surely VAR has failed again. That ball for Japan's second goal looked out. VAR will struggle to get out of the group stage.'
'Not sure how VAR has given that Japan goal,' another bemused fan tweeted. 'Whole of the ball looked out.'
The decision reached by VAR did receive some backing.
'It's the absolute apex on the circumference of the ball that counts, and it looks like that's still in play to me...' one fan said.