According to the former Manchester United star, both are surreal in their own fashion but Lionel Messi edges Cristiano Ronaldo because one gets the impression that he is just 'having fun' while tormenting oppositions.
Rooney chose Lionel Messi ahead of his ex-teammate, with whom he spent five years at Old Trafford.
Cristiano Ronaldo and Rooney will be remembered as one of the most devastating Premier League partnerships, owing to their flamboyant link-up play, dynamism and the ability to create goals as a pair on a consistent basis.
Despite sharing the dressing room with Cristiano Ronaldo, Rooney admitted that the Portuguese wasn't as focused on recording goalscoring numbers during the early stages of his career.
"Cristiano Ronaldo ruthless, but Lionel Messi will torture you," says Rooney
Lionel Messi and Cristiano Ronaldo are arguably the greatest players to have ever graced the game.
While there are a slew of footballing greats that divide opinion on who is the finest player of all time, Lionel Messi and Cristiano Ronaldo have fabricated a parallel world of their own where every single year, one aims to outproduce the other in terms of numbers and trophies.
We may not ever see two world-class footballers of this standard lock horns against one other this way, as indicated by the 10 years of dominance at the Ballon d'Or podium.
Starting from 2008 until the year Luka Modric broke the duopoly, Lionel Messi and Cristiano Ronaldo won five Ballon d'Ors each.
Rooney, admitting that the duo are the greatest the game has ever seen, spoke about Cristiano Ronaldo saying:
"Ronaldo wasn't as focused on goals when we started playing together but you could see that all he wanted was to be the best player in the world. He practised and practised and began to produce. Cristiano has become an incredible scorer and he and Messi are arguably the best two players the game has seen."
Indeed, Lionel Messi recently recorded 1000 goal contributions in his senior career for club and country, scoring scoring 703 and adding 297 more assists.
Cristiano Ronaldo, who has 735 goals in his illustrious career, keeps the records tumbling as he earlier became the fastest player in Serie A history to score 50 goals. He also became the first player to win three titles in Europe's top five leagues.
Rooney, however, chose Lionel Messi ahead of his former teammate. He added:
"Ronaldo is ruthless in the box, a killer. But Messi will torture you before he kills you. With Messi you just get the impression he is having more fun. Those two have completely changed the game in terms of goalscoring numbers and I don't think they'll ever be matched."
Both Cristiano Ronaldo and Lionel Messi meanwhile, are preparing to steer their respective teams to Champions League glory in the coming days.