Tottenham boss Antonio Conte suggested referees and VAR officials are letting the Premier League down and said England could follow Italy's example to improve standards after his side's 3-1 defeat at Arsenal.
Conte was speaking after seeing Emerson Royal shown a straight red card by Anthony Taylor in the second half for a tackle on Gabriel Martinelli.
The Gunners soared four points clear at the top of the Premier League table after goals from Thomas Partey, Gabriel Jesus and Granit Xhaka gave them a deserved victory at the Emirates Stadium.
Spurs, who had levelled through Harry Kane's penalty, capitulated in the second half and were unable to recover after Emerson's red card.
Conte, who initially said he did not want to comment on the decision, then unwound and insisted that the standard of officiating is not good enough.
"In England I have to be honest, it is very difficult because there isn't the same line," he said.
"Sometimes you see a situation that could be a red card and instead is a yellow card or no yellow card, sometimes you see a situation that is a yellow card and you see a red card.
"They have to work a lot about this. In Italy, they go on Thursday and stay together for three days to work together, to look at the video and try and improve.
"I don't know if they do that in this country but it would be a good idea because the level is so high and we need the level of the referee and VAR the same.
"The Premier League is a really high level and for this reason every part of this situation has to be top.
"Honestly, for sure the player is frustrated because he knows what happened, he knows the difficulty we had after the red card. It can happen.
"Emerson is a young player, he is only 23, I think he has to try and exploit this situation to be better and in the next situation avoid totally the tackle.
"Honestly, the player was really surprised, not only him, but all of the players."
The Gunners were full value for their victory, gaining revenge for Tottenham's win across north London in May, which effectively condemned their opponents to the Europa League.
They opened the scoring through Partey's fine 25-yard strike and, after Kane scored his 14th goal in 18 north London derbies from the spot, Mikel Arteta's side stepped up after the break.
Jesus bundled home after a poor Hugo Lloris error and moments after Emerson's red card Xhaka killed the game.
The three points continued Arsenal's excellent start to the season and Arteta believes that victory in this game should give his players belief they can challenge at the top this season.
"For me the message is to the players and everybody here at the club that we are able to play at this level against this kind of opponent," the Spaniard said. "That should give them confidence and belief.
"It's great. Looking at the table and seeing the club in this position is great. It gives you a great feeling obviously. But we are focused.
"It's a really hungry and humble team, believe me. It's nothing that we have done yet and there's still a lot of things to improve. That's the direction we're taking.
"We just started and we're really happy with where we are. The table says what it says and we don't look at that.
"Great performance, a great day. It was an incredible atmosphere to play in so I'm so grateful to the people who connect to the team in such a special way.
"I'm really happy because it's an opportunity to get a lot of people happy and proud and I think we delivered that to all of them."