Mourinho happy to be 'home' for Christmas
Moyes return
"I think 35 for him is the same as 25," Mourinho said.
"He scores goals, plays well, I'm really happy for him because he will end his career on a high, not in America or China. He's ending his career at the top.
"His record is good. He can improve. With no penalties, that is amazing too. Normally other guys that are top scorers have a lot of penalties.
"He had one penalty in 17 matches. I couldn't be happier with him."
The United manager is still without Luke Shaw (groin injury), but otherwise has a full complement of defenders to choose from, with Marcos Rojo, Daley Blind, Phil Jones, Chris Smalling and Eric Bailly available.
Sunderland boss David Moyes returns to Old Trafford in charge of a team for the first time since he was sacked by United in April 2014.
Moyes lasted 10 months in the job after succeeding Alex Ferguson, but has no regrets about leaving Everton for his ill-fated stint.
"My time there was too short, but as I have said many times, you have to win games and I didn't win enough games," said the Scot.
"I would do it again, 100 percent. Very few people are offered the job at Manchester United and I was honored to be offered it.
"It was a great experience and one I wouldn't change because of the quality of the players and professionalism I found."
Former United players Donald Love and John O'Shea start for struggling Sunder-land, which is in the relegation zone.
However, Adnan Januzaj is not eligible because his on loan from United.
"I will feel that I'm going into a difficult game and for us to get a result we will have to play really well," said Moyes.