Ronaldo scored twice in los Blancos' 3-1 success over the Blaugrana on February 12, and though Messi fired home an equaliser at the Santiago Bernabeu on Saturday, the Portuguese's emergence from the bench ensured a 2-1 victory.
"Messi cannot save every game for Barcelona," the former Al Wasl trainer told Marca. "Ronaldo is a wonderful player. He is in a fantastic shape, but Messi is still better, even after the defeat of his club. "
The 52-year-old also revealed that he misses mentoring the Argentina star since he lost his position as Albiceleste coach following their World Cup 2010 exit.
"I love Messi, I would like to be his coach [again] some day," Maradona said.
Barcelona currently tops the Liga table with an 13-point advantage over Madrid in third place.