The Selecao captain was forced off the Stade de France pitch in the 25th minute with a knee injury suffered in a strong tackle from France star Dimtri Payet.
Ronaldo tried on a couple of occasions to receive treatment in a bid to get himself back into the contest but succumbed to the problem before doing everything he could from the touchline to get the Portuguese over the line, prompting the following words from Santos.
"Our skipper (Ronaldo) put in an immense effort," Santos said. "He has amazing team spirit.
"Twice he tried to get back on the pitch but him being there in the dressing room and on the bench was very important for us.
"He believed - just like myself - that tonight was our night."