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.
But the newly introduced Video Assistant Referee called the referee's attention to Nani being in an offside position, leading to the goal being ruled out.
Mexico responded well to going behind, and hit back through top scorer Javier "Chicharito" Hernandez on 42 minutes, when he headed in a Carlos Vela cross.
Portugal captain Cristiano Ronaldo insists there is no reason to be alarmed by their opening draw in the Confederations Cup.
Both teams are trailing hosts Russian Federation in Group A, who beat New Zealand 2-0 in the tournament opener on Saturday. New Zealand is at the bottom of the group with no points.
As Bleacher Report noted, the match could be something of an uphill climb for El Tri as they face one of the best-playing teams in the world right now.More news: Trump tweet confirms he's being probed by prosecutor
"It is a little hard for the players", Chile coach Juan Antonio Pizzi said. We've prepared thoroughly and we just have to expect that the players play properly and execute the game plan.
The Portugal skipper could not control the ball to shoot but his brilliant pass between three defenders left Quaresma free to round keeper Guillermo Ochoa and tap into the empty net.
"Since I joined the national team I've felt very welcomed", Silva said.
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.
It will be European champion Portugal, with Cristiano Ronaldo in top form, taking on Gold Cup victor Mexico in a game that is likely to decide the group victor.
The FIFA Player of the Year, who had scored 11 goals in seven games coming into Sunday's encounter, was perhaps not as influential as usual but was still named man-of-the-match.
Cristiano Ronaldo, battling accusations of tax evasion and speculation over his club future, is concentrating only on the Confederations Cup, his Portugal teammate Andre Silva said.