The Portuguese forward started the Champions League semi-final first leg following three weeks out of action with a knee injury, but he admits that he did feel nervous before the game.
"I was afraid - it was my first match after three weeks out," Ronaldo told reporters. "Some people didn't want me to play and some people did. I felt well and ready for the next few games.
"1-0 is a good result. We have a good advantage and if we score next week it will be so difficult for them to qualify for the final."
The second leg takes place at the Allianz Arena next Tuesday.