Agbonlahor has started the season in sensational form and was at his very best on Saturday with an inspirational performance in Villa's 2-0 victory over Wigan.
Having scored a fine solo goal to break the deadlock, the forward then demonstrated his lightning pace to set up Darren Bent for Villa's second.
Petrov has been so impressed that he feels Agbonlahor now deserves greater recognition, while he has challenged the 24-year-old to maintain his current level.
"People talk about Ronaldo, but when you look at the assets of Gabby, you can put him in the same bracket," Petrov said in the Daily Star.
"I have always said to him, 'You don't know how good you are and the ability you have'. He can take this Premier League by storm. Not many people have what he's got.
"He has the strength, the speed, he scores goals and he creates them. I'm trying to give him the encouragement.
"I thought Gabby was absolutely outstanding in the win over Wigan. That's the Gabby we know, taking people on.
"Players are so scared of his pace. The game against Wigan was all about Gabby. He was brilliant."
Petrov insists there are other Villa players with the potential to achieve greatness, and all they need to be successful is a bit more self-belief.
He said: "We have players with unbelievable talent. We want them to show just what they can do regularly.
"We saw what Gabby was all about against Wigan. Every time he got the ball they were scared."
Source: Team Talk