That is according to Liverpool legend Steven Gerrard, who won the competition back in 2005 with the Reds.
Ronaldo has scored eight goals in the knockout stages so far for Real Madrid, including hat-tricks against Bayern Munich and Atletico Madrid in the quarter and semi-finals.
Juventus are looking to win the Champions League for the first time since 1996 and Gerrard thinks it will be a tight match.
"I predict a cagey affair, I think this one could go right to the wire," he said on BT Sport.
Juventus v Real Madrid combined line-up Sat, June 3, 2017
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GK: Gianluigi Buffon
Steven Gerrard believes Cristiano Ronaldo gives Real Madrid the edge over Juventus
I just think with Cristiano Ronaldo and having Gareth Bale on the bench, it could give Real Madrid that slight edge
Steven Gerrard on Juventus v Real Madrid
"I just think with Ronaldo and having (Gareth) Bale on the bench, it could give them that slight edge."
As Gerrard said, Real Madrid winger Gareth Bale is set to start the game as a substitute after missing the last month of the season through an ankle injury.
With the game being played in Bale's hometown of Cardiff, Gerrard thinks he could be the match winner from the bench.
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Steven Gerrard says Gareth Bale could be the match winner for Real Madrid against Juventus
"You certainly wouldn't rule it out, a player with his class and ability," he added.
"I think that is the sensible decision to have him on the side in case they can't make the breakthrough and maybe Gareth's the man to get all the glory in the end, what a story that would be."
Bale has already won two Champions League titles since his world record move from Tottenham four years ago.