Pep Guardiola called for someone to explain "what is going on" with VAR after Manchester City were controversially denied a penalty in their 5-2 win over Southampton.
Referee Jon Moss failed to point to the spot after Phil Foden appeared to be taken down by Saints goalkeeper Alex McCarthy and VAR did not intervene in an eventful game at the Etihad Stadium.
City ultimately won convincingly to extend their lead at the top of the Premier League to 14 points with both Riyad Mahrez and Kevin De Bruyne scoring twice.
Yet it was the contentious penalty incident, which occurred with the score at 1-1, which remained the main talking point.
McCarthy went in feet first on Foden and appeared to catch him on the ankle after the City midfielder had pounced on a mistake by the keeper.
"There are things that are hard to understand," said City manager Guardiola, who also highlighted some other recent VAR controversies involving other clubs.
"So maybe one day they can explain the rules about the VAR. Hopefully one day they can explain what is going on.
"Jon, the referee, OK he cannot see it, the linesman cannot see it, (but if) the VAR cannot see it – Oh my God.
"You just want it to be more clear, and the right decisions. We won 5-2 but if we'd lost 5-2 I don’t make any comment. After you win you can do it, if not it looks like an excuse."
It is understood that, in making his decision, Moss will have thought that McCarthy got a slight touch on the ball and VAR did not see conclusive proof that he did not.
Cynics might suggest that had Foden not quickly got back to his feet he may well have been awarded the spot-kick.
That certainly appeared to be the view of Leicester midfielder James Maddison, who was presumably watching the game on TV.
Maddison tweeted: "Being honest and getting straight back up to try and score like Phil did is punished… because if he stayed down after initial contact and rolled around and screamed, I’m almost certain he would have been awarded penalty. So where’s the incentive to stay on your feet?"
Former Liverpool captain Graeme Souness was also forthright on the matter.
Souness told Sky Sports: "Say they’d drawn and he (Foden) hadn’t stayed down he’d be getting stick from everyone. That was a very obvious penalty.
"It is a classic case of the matchday referee calls it or doesn’t call it and the ones at Stockley Park support him. They make themselves look really foolish. That was (clear and obvious). The referee got that wrong."
Guardiola felt Foden deserved credit for his reaction.
"The thing that made me so proud was the honesty from Phil," Guardiola said.
City, perhaps suffering a hangover from their derby loss to Manchester United, started sluggishly.
They did take the lead through De Bruyne but were pegged back by a James Ward-Prowse penalty.
After their own spot-kick controversy, it took two moments of brilliance from Mahrez to change the game, first scoring a fine goal and then setting up Ilkay Gundogan after another shot hit the post.
Mahrez and De Bruyne then struck either side of a Che Adams effort in a frantic few minutes early in the second half.
Guardiola said: "In the first 20-25 mins, they were best team we've faced all season, home and away. I have only respect and admiration for Ralph’s (Hasenhuttl) team and the way they play. We suffered a lot to control them. They were brilliant. It was a tough game but an incredible victory."
Hasenhuttl felt his side played well but admitted they did not deserve anything from the game.
He said: "No, because they had more chances than we had, but I think we can discuss the way we played.
"Their second goal turned the table a little bit. Until that moment we had a fantastic game. This is what I wanted to see, a brave performance.
"The third goal changed the atmosphere before half-time. In the second half we were sitting deeper because a few players were a little tired but this is not possible in such a game because they are immediately too strong."