Juan Antonio Pizzi calls for calm over VAR: 'This system needs time'
Video reviews are not giving FIFA a quick enough solution at the tournament it is using to fast-track the system for the 2018 World Cup.
Both Confederation Cup games played on Sunday in Russia left teams confused by decisions -- reached more slowly than expected -- by referees taking advice from assistants watching multiple replays.
Portugal and Chile both had goals disallowed for offside. Portugal had to wait for what seemed an unnecessary review of a good goal scored.
FIFA has told referees they must use reviews to overturn only "clear errors" in game-changing situations such as penalty kicks awarded and offside rulings affecting goals.
In trying to define a clear error, FIFA has suggested when "almost everyone who is neutral agrees the decision is incorrect."
Portugal ended 2-2 with Mexico and, perhaps fortunately for FIFA, Chile beat Cameroon 2-0.
"I think this system needs time. If I am right, we are trialling the system right now so it's difficult as we are used to another system in the world of football," Chile coach Juan Antonio Pizzi said.
"At the end of the first half we could have been 1-0 up but 20 minutes later we were still level and that made the players disappointed. It's true it caused distress but that's because we are not used to it. We will have to wait and see how it develops.
"It's true that maybe the situation had an impact on our performance in the second half. It was a fair decision but it's difficult as before this tournament the goal would have stood.
"The only negative comment was that it's difficult for the players' feelings during the game. Even if the right decision was reached it has an impact on the players."
Chile's star player Arturo Vidal fiercely argued with referee Damir Skomina when a goal scored in first-half stoppage time by Eduardo Vargas was overruled almost one minute later. FIFA later released still images of a razor-thin margin of the offside ruling.
"It's the first time our team has played with this new technology and when we were on the pitch we were very concerned," Vidal said after the match.
"In the moment it's not easy to accept but it's fair and it will be useful."