The Juventus forward became the second male player to reach the landmark of 100 international goals, netting a brace in Portugal’s 2-0 win over Sweden in the Nations League.
Ronaldo is chasing down Ali Daei’s world-record tally of 109 goals for Iran.
The 35-year-old opened the scoring with a stunning free-kick from 25 yards, giving his side a 1-0 advantage going into half-time.
The captain then doubled the lead with another brilliant curling effort from the edge of the box to hand Portugal all three points in their Nations League clash.
Ronaldo had missed Portugal’s 4-1 win over Croatia on Saturday with a toe infection, but recovered to start Tuesday night’s match in Solna.
He also picked up the first of his five Ballon d’Or trophies in 2008, scoring 31 league goals in Sir Alex Ferguson’s title-winning side.
United clearly still have some affection for their former star, and posted the following message on their social media: ‘Congratulations to former #MUFC star #Cristiano #Ronaldo on reaching a century of goals for Portugal! 👏’