Messi, 23, has been crowned the world's best player for the past two years and has every chance of making it a hat-trick if he continues the outstanding form that has seen him score 52 goals in 51 games this season.
Rooney's record for Manchester United has been a comparatively modest 14 in 35 but Ancelotti, who will be hoping his defenders can prevent the England striker from scoring in this Sunday's Premier League title decider, believes the 25-year-old is more of a team player and claimied he would sign him over Messi if the opportunity arose.
"Everyone goes for Messi but I would take Rooney," Ancelotti told the Daily Mail. "Messi is out of this world and maybe he is reaching the level of Maradona.
"Rooney, however, is closer to the reality of football. He puts his talent out to the rest of the team and this explains the difference between players and outstanding players."
But despite his admiration for Rooney, Ancelotti insists he will not be focusing on man-marking the former Everton forward at Old Trafford, where the Italian boss also feels Ryan Giggs will be a major threat.
"We want to play our football, not just control their skills and ability," Ancelotti said. "Rooney is the key player for United, and the last time against us Ryan Giggs was the best player. He passed three balls and they scored three goals."