Moments later, Javier Hernandez tied the game with his fourth Confederations Cup goal.
Ronaldo was making the headlines on Friday because of a report that said he wants to leave Real Madrid and Spain following allegations that he defrauded the country's tax authorities. We were at least as good as they were.
With that, the result now gives both of the teams one point, a fair result.
Portugal is making its first appearance in the Confederations Cup, the eight-nation competition played by continental champions plus host Russian Federation and World Cup victor Germany. The result leaves hosts Russian Federation on top of Group A after they beat New Zealand 2-0 on Saturday.
The match in Kazan will start at 1500 GMT and will be followed at 1800 GMT by the Group B opener between African champions Cameroon and Chile in Moscow.
The duo scored goals in the same match three other times - World Cup qualifiers against Hungary, Andorra and the Faroe Islands. It is played by the continental champions plus the host nation and the World Cup victor.More news: Record-breaking Real Madrid beat Juventus, retain Champions League title
Reacting to the result, Osorio said, "Let me repeat what I said before, I think that we played against a very strong team and I think we performed pretty well".
"He takes this tournament very seriously and is focused". He also scored important goals in the decisive stages of the Spanish league, a competition Madrid won this season for the first time in five years.
As is often the case, Ronaldo thundered his set-piece straight at the wall after lining up for it, but showed excellent skill to crack a left-foot shot at goal in the aftermath that bounced back off the bar.
A good performance at the Confederations Cup will virtually secure him a fifth world player of the year award, equaling Lionel Messi. A year ago I said that Portugal were going to Euro 2016 to win it. "I have the same confidence today", Portugal coach Fernando Santos said earlier this week.
Last year's triumph at Euro 2016, when Portugal defeated France in the final to emerge as European champions for the first time, ended Ronaldo's lengthy wait for global glory.
But Mexico responded with Hernandez testing Portugal keeper Rui Patricio, before putting his side level. Portugal won 1-0 in a friendly in 2014.
They will be led by former Barcelona defender Rafael Marquez, still going strong at 38 - while Ronaldo will win his 140th cap in the game, Marquez will be making his 139th worldwide appearance.
Defender Miguel Layun and midfielder Hector Herrera play for FC Porto, while forward Raul Jimenez plays for Benfica. Ten of its players are with Portuguese teams.