Mexico equalised eight minutes later through a Javier Hernandez diving header after poor defending by the Portuguese.
Participants in the 2017 Confederations Cup are hosts Russian Federation, 2014 FIFA World Cup Champions Germany, 2015 Copa America Champions Chile, 2015 AFC Asian Cup Champion Australia, 2015 CONCACAF Gold Cup winners Mexico, 2016 UEFA Euro Cup champs Portugal, OFC (Oceania Football Confederation) Nations Cup victors New Zealand and 2017 CAF Africa Cup of Nations Champion Cameroon.
"I had never been in favour of VAR technology, but I must admit it's necessary now". Ronaldo magnificent pass found Quaresma, who is nobody to prevent to score into an empty net.
Portugal led twice but were left frustrated as they switched off at the death, Moreno heading in from a corner.
Nani's 21st minute goal was disallowed by video assistants because a Portugal player was offside in the build up to the goal.
However, the crowd had no idea what happened, and the replays and thought-process of the video assistant referees weren't even made available to the viewing public.
Almost twenty arrested as thousands protest verdict in Philando Castile shooting
Before Castile completed the sentence, Yanez interrupted and replied, "Okay" and placed his right hand on the holster of his gun. It was the first time in the history of the state that a police officer was charged in a fatal shooting that happened on duty.
Cristiano Ronaldo has now scored or assisted in each of his last seven games for Portugal.
After an explosive opening period, the second was a much tamer affair as both teams squandered half chances as the tempo dropped.
He said: "It was not the result we wanted, the team had the game nearly won and we conceded a goal in the last minutes, but that is football".
Ronaldo's backheel then saw Quaresma fire narrowly wide but another defensive error allowed Mexico to draw level three minutes before the break.
Having bounced back into the box, the ball was eventually diverted home by central defender Pepe, who is also Ronaldo's team-mate at UEFA Champions League winners Real Madrid.
Mexico weren't down and out though, demonstrating their incredible team spirit to storm back with a stoppage time equaliser, ensuring the two teams took a point each.