Global soccer body FIFA have said that they would prefer VAR to be used once every four games rather than four times in a match, buy in Saransk on Monday, it was used for three decisions in the second half -- and each time the arguments continued.
The repeated use of the technology appeared to contribute to a bad-tempered second half which saw players feigning injury and repeatedly mobbing the referee.
FIFA rules state that players should receive an automatic yellow card for drawing a television screen in the air, but that did not stop them from verbally pressuring Paraguayan referee Enrique Caceres, who had a torrid time.
The first VAR decision was in the 50th minute when Ronaldo got the ball on the edge of the Iran area, cut across it, collided with a defender and fell dramatically to the ground.
The referee initially told him to get up but then consulted VAR and gave a penalty, which Ronaldo took only for Alireza Beiranvand to save it.
Ronaldo was again involved in the 81st minute, this time in an off-the-ball tussle with Morteza Pouraliganji who suddenly collapsed to the ground, prompting excited protests from Iranian players.
Television replays suggested that Ronaldo struck Pouraliganji with his elbow, a clear red card offence, and when the referee decided to review the incident on his pitchside monitor, it looked like curtains for Portugal's captain.
The referee returned to the pitch, went for his pocket -- but pulled out a yellow, rather than red, card.
Even more controversial was his decision to award Iran a stoppage time penalty.
Sardar Azmoun headed the ball down against Cedric Soares' arm from point-blank range and it appeared impossible for the Portugal right back to get out of the way.
Once again, amid excitable protests, the referee decided to check VAR and, to Portuguese disbelief, gave another penalty which was converted.
Clearly rattled, Portugal nearly conceded a late goal which would have dumped them out of the tournament.
The use of VAR has been praised for lifting the pressure off referees and reducing the risks of headline-making mistakes which have marred major tournaments in the past.
As Monday's game showed, however, it can just as easily muddy the waters.
"In the rules, an elbow is a red card, it doesn't matter if it's Lionel Messi or Ronaldo," said Iran coach Carlos Queiroz, who complained that VAR decisions were not transparent.
"We need to know what's going on and nobody allows me to see," he said. "You have one system which costs a fortune...and nobody takes responsibility. When there is a decision with VAR, we need to know who is refereeing the game."
(Writing by Brian Homewood; Editing by Ian Chadband)
