Ronaldo, 33, was sent off in the Champions League for the first time during Juve's 2-0 win over Valencia on Wednesday.
Allegri has dismissed any claims Ronaldo needs to prove a point at the Stadio Benito Stirpe, saying the five-time Ballon d'Or winner has already done so throughout his illustrious career.
"He will have a great performance as he did in the first 30 minutes in the Champions League," he said.
"Everyone always has very high expectations of him but do you think he still has something to prove? I think he simply needs to play and enjoy himself, scoring goals as he always does. He has already proved everything in his career.
"He is a very a demanding player, especially with himself, so I'm sure he will play a great game. Wednesday's episode is already in the past."
Ronaldo has scored two goals in five games for Juve since arriving at the club from Real Madrid in July.