Ronaldo netted a hat-trick on Tuesday to steer Juve into the quarter-final stage of Europe's elite club competition.
And after Messi responded with a sublime showing himself in a record-breaking night, he was asked about his rivals' achievement.
"What Cristiano Ronaldo and Juventus did was impressive," the forward said after the Lyon match, as per Marca.
"I thought Atletico Madrid would be tougher. Ronaldo had a magical night with three goals."
Messi and his teammates will soon find out if they'll face Ronaldo and Juventus in the next round, but the 31-year-old isn't thinking about that.
"All of the opponents are complicated," he said. "Ajax, for example, showed that they're an amazing team of youngsters and they don't fear anyone.
"It'll be difficult no matter who we face.