Maradona and Pele are widely considered to be the two finest players of all time, but Messi's one-time teammate Gudjohnsen thinks that the Real Madrid and Barcelona stars are their equals of this generation.
"When you look at those two, Cristiano Ronaldo and Lionel Messi, it is like watching Pele and Diego Maradona at the same time," he told Sky Sports News.
"They're that good. They're not the World Cup stars as those two were but in modern day football, their achievements are as good as anything.
"You have the feeling that Ronaldo has been in the shadow of Messi for a long time, but in recent times, he has come out of that and posed the question who is the better player."
You can catch live commentary of this evening's El Claisco between Ronaldo's Madrid and Messi's Barcelona by clicking here.