Lokomotiv Moscow coach Yuri Semin considered stopping Ronaldo an impossible misson.
It kicks off on Tuesday at 20.00 UK time (19.00 GMT) in Turin.
“I thank Maurizio Sarri and Juventus for the compliment in saying we are a dangerous opponent,” said the 72-year-old tactician in his press conference.
“The trip to watch Juventus play Bologna on Saturday was certainly worth it. They put in an astonishing performance, as always, and we gained some useful information.
“They play more attacking football this season, pass it more in the opposition half, but also I noted they win the ball back much quicker when it has been lost. They are certainly one of the candidates to win the Champions League.”
Lokomotiv Moscow are in an injury crisis, with Anton Miranchuk, Jefferson Farfan, Fedor Smolov and Maciej Rybus all long-term absentees, now joined by Luka Djordjevic.
“Nobody has been able to stop Ronaldo yet in his career, so why ask me how to do it? The whole team has to work together to stop all of Juve, because this is a squad packed with star names. The attention cannot just be focused on one player.
“We did talk to Benedikt Howedes about his time at Juve, but not just that. He has a good eye and can sense certain things.”