Ronaldo equalised from the penalty spot in the 68th minute against Croatia with a fine penalty which was followed up with finish from Goncalo Ramos near the death to seal Portugal’s clash with Spain on Monday night.
Spain also hold the historical edge from frequent meetings with Portugal as they have lost just seven of their previous 41 games between the two sides.
Is this Ronaldo's last World Cup?
Despite this, Simon has warned about Portugal and more specifically Ronaldo who is still going strong at 41 years old.
"The Cristiano we have at the World Cup is not the same as six or seven years ago, when he was at his peak.
"But we have to try to keep him as far away from the area as possible. In the Nations League final, he had a ball inside the area and scored. He has that goal-scoring ability that we would all like to have on our team.
"What Cristiano has is that, in the box, he turns himself around to finish, look for through passes, create space... He has great experience and teammates he's played with for a long time and understands everything perfectly.
“If he gets into the box, he's decisive. He reads these situations very well and we have to be prepared for everything.
"I don't think it's Cristiano's last dance. Every game is different. The important thing is to focus on the game and not on what surrounds it in the media."
Five-time Ballon d’Or winner Ronaldo is gracing his sixth World Cup finals and after grabbing his first knockout goal at the tournament, he will seek to make more of an impact against a Spain side who are one of the favourites to go all the way.