The Euro 2016 champions saw a goal disallowed by the extra officials during their opening Confederations Cup fixture against Mexico
Fernando Santos says the use of the Video Assistant Referee (VAR) remains confusing after his Portugal side saw an opening goal ruled out against Mexico at the Confederations Cup.
The two teams ended up drawing the game 2-2, with Hector Moreno nodding a late equaliser, and there was controversy when Nani's 21st-minute effort was disallowed for offside - with the use of VAR - before Ricardo Quaresma's opener.
While the VAR appeared to come to the correct decision, Santos was frustrated that this came only after the officials had looked at an earlier phase of play where Pepe was offside.