The defender with a fearsome reputation for his tackling could not control his emotions after his team's 1-0 extra-time defeat of France in the European Championship final, which delivered Portugal its first major global football title.
"It's one of the happiest moments of my career".
Ronaldo tried to run off the injury, but repeatedly reached down with his right and left hands to gently press his knee.
Coach Fernando Santos said the "ugly duckling has become beautiful" after Eder, jeered by Portugal fans during a game in March, fired in a long-range goal 11 minutes from the end of extra-time to give Portugal an unexpected 1-0 win. "But for the moment I'm thinking about my teammates".
The win also helped make up for Portugal's loss to underdog Greece when it hosted the Euro 12 years ago.
Even France forward Antoine Griezmann, the tournament's leading scorer, couldn't rise to the big occasion.
Looking tense and emotional, Ronaldo went between players with hugs and words of encouragement before taking a seat in the dugout to watch the rest of the final.
Cristiano Ronaldo only showed flashes of brilliance, as did Nani and Ricardo Quaresma, so it's no surprise that the only Portuguese players in Opta's statistically-devised team of the tournament play further back than the three creative outlets.
'This time we didn't manage it, unlike against Germany. By nearly all criteria -quality as a team, recent victory over Germany, game being played in France and seasoned players- France should have been victorious.
"Cristiano told me I would score the winning goal.
I cried", said Ronaldo, who later, despite his injury, danced his way through the mixed zone in Paris with several teammates, without stopping for waiting reporters.
"I'd like to thank my team-mates, our coach, our wider team in this Euro, the Portuguese people and all the ex-pats who were always with us, cheering for us from the beginning".
"I understood that Eder was the player who had to come on to hold up the ball in attack and create problems for France in the air", Santos said. I injured myself in the first few minutes. Hugo Lloris, the French team captain said, "Football can be very cruel".
France, however, nearly clinched a victory when substitute Andre-Pierre Gignac turned and hit the ball inside of the post at the end of normal time.
"We weren't clinical enough, we weren't cool-headed enough".