Ronaldo was at Inter for four seasons after joining for a world record fee in 1997 and, although he scored plenty of goals in the first two, the way he left, after the club had supported him during a two-year injury nightmare, upset many fans.
"Ronaldo... was one of the three best players of all time in my opinion," Hernanes told reporters. "Like all left-footed players I like (former Inter and Uruguay forward Alvaro) Recoba, plus he was in a different class. He really impressed me."
Hernanes joined Inter in the January transfer window after 3-1/2 seasons at Lazio and spoke glowingly of his new club's past.
"(Inter) are the only club to have never been relegated to Serie B. This is proof that it's a serious club that knows how to get results," he told a news conference.
"Then there's the fact that Inter were never caught up in the scandals that hit Italian football a few years back. I'm pleased about that.
"I'm someone who likes to steer clear of controversy, that's why I always do what's right and fair. Being at a club like this strengthens my attachment to the cause."
He then spoke of his World Cup hopes.
"I think Inter will give me even more credibility in terms of the national team. It was a big move, I've made a step up. It will certainly be important for the World Cup," he said.
Hernanes did not start a game at the Confederations Cup last year although he made five substitute appearances.
One of his problems is that he is usually seen as a deep-lying midfielder who likes to push forward, whereas Brazil coach Luiz Felipe Scolari prefers players in that position to perform a purely destructive role.
"I like to play either inside left or right. I've played central midfield in the national team, one of the two Scolari uses, while at Lazio I played attacking midfield," he said.
"I spoke to the coach (Scolari) about my position and told him what my preferred role is. But when I first started playing football, aged 14, I played right back.
"I've played in almost every position. I like playing in midfield, but it depends what the coach needs from me. Basically I don't mind playing anywhere."
(Reporting by Brian Homewood; Editing by Ken Ferris)
