The England international scored twice at Old Trafford to take his tally this season to 17 goals, and Mata has been impressed with his recent form.
"He's doing very well for us, scores almost every game and is so passionate about playing for this club," he told MUTV. "I'm very happy for him and hopefully he can keep scoring until the end of the season.
"I really enjoyed linking up with him as we had spaces to play between their lines. I really like to play with him because he is top striker - he does."
Rooney is third in the all-time list of Manchester United's top scorers with 214 goals.