Ronaldo scored a stunning overhead kick in Real Madrid's 3-0 Champions League quarter-final first-leg win over Juventus in Turin, having earlier broken the deadlock with a precise close-range finish.
The Portugal forward's second goal earned an ovation from the home fans at the Allianz Stadium and gave Madrid a crucial advantage in the tie, before Marcelo added a third after Paulo Dybala was sent off for the Italians.
Buffon could only express his admiration for Ronaldo and Barcelona star Messi in the wake of the dispiriting defeat.
"We saw what Ronaldo has always been: a player of an extraordinary level, who is achieving the highest things, along with Lionel Messi," Buffon told Mediaset Premium.
"They should be compared in their value to Maradona and Pele for the way they ultimately are able to decide the matches and trophies their teams win."
It is a sentiment that Real Madrid manager Zinedine Zidane shares, as he specifically made mention of Buffon's comment to agree with it, speaking to reporters after the match.
"I was happy with the second goal, the gesture was spectacular," Zidane said. "Buffon is right: you have to take off your hat with these players you named. Messi and Ronaldo are as influential as Pelé and Maradona."
Meanwhile, Buffon, who has never managed to win the Champions League in his storied career, admitted it was a massive blow to see the tie effectively killed off even before the second leg at the Santiago Bernabeu.
"Mistakes can happen," he said. "You're playing against top champions and they force you into being less precise than usual. You're facing the best and there's a reason a player has scored 500 goals.
"I feel great regret and disappointment because we probably won't be able to progress. It's a regret, a big regret, but it's also true that, when you meet certain opponents, you must have a clear enough head to recognise they are stronger."
Juventus will try to overturn their deficit April 11 in the second leg at the Bernabeu.