The Real Madrid icon made his return to a Portugal side that had struggled for goals in recent games.
Remarkably though, the Real Madrid star, Portugal's record goalscorer, failed to make it on the list of those that found the net.
Ronaldo had missed the 0-0 draw with Greece in Lisbon at the end of May though injury, as well as the narrow 1-0 victory over Mexico on Friday, which was only decided by an injury time Bruno Alves header.
The Portuguese skipper's very presence seemed to fill his teammates with confidence against the Irish, who were shambolic in their defending at times. Hugo Almeida scored a first half brace, with a Richard Keogh own goal, and strikes from Vieirinha and Fabio Coentrao adding gloss to a win only punctured by James McClean's first goal for his country.
Ronaldo had to make do with having a hand in two goals, as well as hitting the post from a trademark free kick, but even better news is that he managed to play a decent 65 minutes ahead of Portugal's crunch World Cup opener with Germany next Monday.
Portugal are ranked 4th in the world, and have high hopes of an impressive tournament in a country they have close ties to. It is likely to be Ronaldo's last World Cup tournament as one of the top players in the world, with the former Manchester United winger set to be 33 when Russia host the 2018 spectacle.
As the present Ballon d'Or holder, and having earned his first Champions League trophy since moving to the Bernabeu, Ronaldo is sure to be on form in Brazil. The question will now be, can he add to his tally of 58 goals this season for club and country to fire Portugal to a debut World Cup win?