Jones joined the Red Devils during the summer for a reported £16.5m and his performances so far have earned him a call up to Fabio Capello's England squad.
"Phil Jones has been unbelievable to be honest," Rooney told Sky Sports News. "He's still only 19 but when you see him play he's playing without fear.
"Now he's been called up to the England squad which is great for him."
Centre-back Jones has made seven appearances for the Premier League leaders this season.