Rome: The VAR system should be used sparingly, as a "parachute" for the referee, when it is introduced into the Champions League for the first time next week, European refereeing boss Roberto Rosetti said on Wednesday.
Rosetti, UEFA's chief refereeing officer, avoided direct criticism of the way VAR has been used in domestic competitions but said that he wanted to get back to the original idea which deployed it only to correct glaring errors.
VAR was widely considered a success at last year's World Cup in Russia but has been contentious in some of the domestic leagues where it has been introduced such as Italy's Serie A, where officials have been criticised for being overzealous.
In one of the most unusual decisions, bottom-of-the-table Chievo had a goal chalked off in a game against Fiorentina last month.
Chievo's Emanuele Giaccherini had the ball in the net after Fiorentina goalkeeper Alban Lafont sent a goal kick straight to him but the VAR spotted an encroachment because a Chievo player had his foot on the line of the penalty area.
Sampdoria's 4-2 win at Empoli in December featured five VAR reviews while Juventus and Sampdoria were both awarded soft penalties with the help of the pitchside monitor in the Turin side's 2-1 win.
VAR will be introduced into the Champions League for the round-of-sixteen ties which start on Tuesday and used for the rest of the competition.
UEFA had backed down from using it earlier because its president Aleksander Ceferin said it caused "confusion" and needed more time to be implemented.
"I don't want to enter into domestic issues but I want to underline that we need to come back to the origin of the project," said Rosetti. "We need to intervene for clear and serious mistakes."
"We want clear evidence, clear images....and serious missed incidents," he added. "The main goal is to be consistent."
Rosetti said that for factual decisions such as offside or whether an incident was inside or outside the penalty area, a recommendation from the video assistant referee would be enough.
For incidents involving interpretation, such as fouls and handball, referees would be expected to view the incident themselves on the pitchside monitor.
"VAR has to be an insurance for the referee, a parachute for the referee, so my wish is that in 31 matches, there are no interventions," he said. "If something happens, we have to be ready."