Portugal's captain scored with a dipping set-piece effort just before halftime to join Ali Daei, who netted 109 times for Iran, on a century of goals.
The 35-year-old was a constant threat to Sweden's back line in the early exchanges, hanging on the shoulder of the last defender before bursting forward to beat the offside trap, but Sweden goalkeeper Robin Olsen was equal to the task.
That all changed when Gustav Svensson received his second yellow card and was sent packing after a reckless challenge on Joao Moutinho on the edge of his own box just before halftime.
Ronaldo stepped up and smashed a dipping effort beyond the despairing dive of Olsen and just under the crossbar before breaking into a wide smile as he celebrated with his team mates.
Sweden were struggling to contain the visitors and Ronaldo struck again in the 73rd minute with another curling, dipping effort, this time from open play, to leave himself just eight goals short of Daei's international scoring record.