Tottenham manager Mauricio Pochettino said he is still not a fan of VAR, even though a video review gave his side their decisive goal in Tuesday's 1-0 Carabao Cup semifinal win against Chelsea.
Harry Kane was initially flagged offside before being fouled by goalkeeper Kepa Arrizabalaga in the first half, but VAR showed he was onside and a penalty was awarded, which Kane converted.
Spurs went on to win the first leg of the semifinal at Wembley, but Pochettino said: "To be honest, I am not happy with that system.
"It is a system that we still need to be agreed [on] in the way we are going to use it. I think a good example is La Liga. No one is happy because no one knows the clear way we are going to use it.
"Everyone is complaining in Spain from day one and I hope that now we have time to develop that system. It needs to be a tool to improve the game.
"Sometimes we cannot talk about football that must be fair, because in different games, for example today maybe Chelsea shoot more than Tottenham. But to talk about fair or unfair, it's about the decision of the referee.
"Sometimes they can make a mistake, like we make a mistake or the players on the pitch. But it is a system that sometimes killed the emotions.
"Of course today it was an advantage for us, a good decision for Tottenham, but I didn't celebrate because we were waiting five minutes.
"People may say, 'This guy is crazy'. When it doesn't benefit us it is easy to complain, but today I need to be clear and honest and I am not happy all too much.
"Some percentage of the referee's mistakes we need to keep. We cannot stop evolution, but how we can help is agreeing with the referees, players and between all the football people how we are going to use it. That is most important."
Chelsea had 58 percent of the possession and 17 shots to Spurs' six at Wembley, but could not find an equaliser.
"I think we were very competitive tonight," said Pochettino. "I am so pleased. We played against one of the best teams in England and in Europe, a team that have been building to win titles. They have unbelievable players.
"I think to win this type of game is an amazing, huge experience for us, to be more mature. Of course it's only half-time, it's a small advantage 1-0. We need to be competitive in the second leg.
"[I need] to give the credit to Chelsea. They pushed a lot in the second half and made us play a little bit deeper. But of course I'm very happy because we were competitive and in the end we won the game."
Spurs' No. 2 goalkeeper Paulo Gazzaniga kept his third clean sheet in a row and Pochettino added: "For me he was the man of the match, with Harry Kane of course who scored the goal. I think he was so good. We are very happy.
"We have one of the best keepers in the world in Hugo Lloris. We have Michel Vorm, another keeper that can play in any club in the Premier League, and now of course Paulo Gazzaniga.
"We have three goalkeepers, plus the younger ones, who have a lot of quality and I am so pleased to have this type of player with us."