Lionel Messi saw a second-half goal ruled out by VAR as Argentina had to settle for a 1-1 draw against Paraguay in World Cup qualifying.
Argentina had fallen behind to a first-half penalty in Buenos Aires when Angel Romero coolly converted after Lucas Martinez Quarta was adjudged to have brought down Miguel Almiron.
Nicolas Gonzalez equalised for Argentina four minutes before half-time when he bulleted a header home from a Giovani Lo Celso corner kick.
But though Messi thought he had completed the comeback by finishing a flowing counter-attack on the hour, VAR ruled out the goal for an infringement spotted at the start of the move.
Argentina coach Lionel Scaloni called for clarity and consistency over the system after the game, saying: "I think there has to be a way of uniting the themes of VAR.
"We are left with a bittersweet taste because Argentina did everything to win.
"In the second half we pinned our opponents back. We also have to recognise the team's attitude in always believing they could win."
The result means both sides remain unbeaten after the first three of their 18-game quest to reach the finals in Qatar.
The top four in the 10-team South American qualifying section automatically make the finals, and the fifth-placed side go into an inter-regional play-off.
Argentina's next game is away at Peru on Tuesday November 17, while Paraguay take on bottom side Bolivia at home the same day.