Tottenham boss Mauricio Pochettino wants to delay the use of video assistant referees (VAR) in the Premier League until the system is improved.
VAR is set to be introduced in the English top flight and the Champions League next season after being used in some domestic cup matches this term.
Spurs lead Chelsea 1-0 after the Carabao Cup semi-final first leg thanks to a penalty awarded using VAR.
“Watching every single game in Europe now, nobody is happy,” Pochettino said.
“I promise you, nobody! What worries me a bit is that there is going to be a situation where football starts to annoy fans.
“This business is so important and our fans – football fans – must be happy. If you stop for five minutes for a decision, I don't know how they are going to behave.”
But Pochettino said after the first-leg victory via a Harry Kane penalty at Wembley he was “unhappy to win like this”.
“For me, I think it is a good idea to delay because if we don't have all the information and don't know how it will work or how we can better develop the system, it is better to stop for one year or more,” added the Argentine.
“The Premier League today is the best spectacle in the world, maybe with the NFL or NBA in America. But certainly it is the best show in Europe or in football.
“So we need to be careful how we develop this system and how we use it.”