The 31-year-old was a doubt to feature in the meeting with Portugal on Wednesday as a result of a head injury picked up in the game prior but played the full 90 minutes wearing a scrum cap as protection.
Ronaldo now has 85 goals for Portugal, more than any other player in history.
Ronaldo is also the leading goal-scorer in the current World Cup with four goals and is a hot contender for the Golden Boot.
Somehow, someway, the Moroccan defence decided not to prioritise marking Cristiano Ronaldo, and the Real Madrid superstar smashed home a header past the helpless Monir El Kajoui. In this World Cup, has scored four goals from just five shots.
The player was withdrawn after 72 minutes against Iran and many Morocco fans feared he would miss the Portugal showdown.
Yet aside from the goal, it was not a vintage display by Ronaldo or Portugal, who were caused problems by a spirited Morocco team.
"From the first minute to the moment I woke up in the hospital, I wanted to play today, I felt good, even though I feel more exhausted than normal".
"I think we are stronger than Morocco if we compare the two teams, but I'm not saying the game will be easy for us", striker Andre Silva told reporters at Portugal's training base.
Portugal coach Fernando Santos has hailed skipper Cristiano Ronaldo as the best player in the world.
The North African nation, beaten 1-0 by Iran in their opening game, are playing at the World Cup for the first time in 20 years. "He is a warrior who wanted to play", said Renard, echoing the refrain that has caused so much damage to sportsmen for decades.
Portugal's misses mattered little, however, as the European champions secured their first win of Russian Federation 2018.