However, Argentinian referee Nestor Pitana called for a review from the video assistant referee and it was eventually ruled that Pepe was one of four players who were offside.
Mexico equalized less than 10 minutes later with a close-range diving header by Chicharito after Portugal defender Raphael Guerreiro failed to clear a ball crossed into the area.
Ronaldo set up Ricardo Quaresma for Portugal's opener, which was duly cancelled out by former Manchester United striker Javier Hernandez, while Hector Moreno snatched a late point for Mexico after a Cedric Soares strike.
That's all that André Silva got in today's Confederation cup game game between Portugal and Mexico (2-2 FT).
The national team next take the field on Wednesday when the face hosts Russian Federation in Mexico.
The result leaves both sides tied for second place in Group A, behind hosts Russian Federation who top the group after beating New Zealand 2-0 on Saturday in St. Petersburg.
Ronaldo took 21 minutes to pose his first threat, forcing goalkeeper Guillermo Ochoa into a smart save after shooting on the rebound when his free-kick was blocked by the wall. And with the imitation of Bavaria's Neuschwanstein Castle looming over the Olympic Park, Germany feels right at home in the 2014 Winter Games host city where it will play two of its opening three matches.
The Video Assistant Referees would again be utilised as Chile's Eduardo Vargas was adjudged to have been narrowly offside before he found the back of the Cameroon net in the first half.
'We played the European champions on equal terms, we generated chances but couldn't finish them, ' said Osorio.
'We have to win, because if we win the next game we will be one step away from qualifying'.
FIFA president Gianni Infantino has described VAR as "the future of modern football" following criticism of the technology during the Confederations Cup.
"When Cristiano was able to run, that put Mexico on alert and we should have done that more often", Santos said after the game in his only reference to Portugal's talisman.