England hitman Rooney has scored six in his last five Manchester United games while Tevez has come to life with three in four.
Fellow Argentine ace Messi has been watching closely and feels the duo could lead Alex Ferguson's men to Champions League glory this season. The Barcelona star said: "Carlos is making a big difference for Manchester United this season.
"His partnership with Rooney is already something special and I think it will only get better.
"Although they play and move similarly to one another on the pitch, they are going to help Manchester United a lot. They will scare defenders everywhere.
"Those who play the game well understand each other immediately. Good players always manage to play well together.
"Barcelona and United are both great teams - and are real candidates for the Champions League."
Tevez, 23, took time to settle following his summer move from West Ham but he is now starting to show his true form. And pal Messi added: "Carlos is always in a good mood and never gets mad. If he is on the bench, he just encourages his team-mates.
"Carlos is also a great singer. The name of his band is Piola Vago. When we were at Copa America, we shared the same room and the music was louder than at a disco."