The Argentine international joined the Red Devils in the summer for £59.7m from European champions and Spanish giants Real Madrid.
Rooney has flourished this campaign since his appointment as club captain at Old Trafford, and Di Maria was quick to praise the England skipper.
Wayne Rooney stats
Manchester United
Games 459 Goals 224
England
Games 101 Goals 46
"Rooney is an impressive player," Di Maria said in an interview with South America's Radio America.
"He plays 90 minutes in every game. He is always committed, giving everything in every match."
Having played with Lionel Messi for his country, and Cristiano Ronaldo, Gareth Bale and Xabi Alonso among others at Real, Di Maria is in a good position to compare his fellow United attacker to the world’s best.
"He has this quality, mentality and this hunger to play every game that is incomparable," he added.
"It is he that has surprised me the most, with his hunger and how he commits to every game. He is a player that deserves to be here."
Di Maria scored the second in United’s 2-0 FA Cup win at Yeovil Town on Sunday after coming on as a second-half substitute.
