Mourinho has hinted at Zlatan Ibrahimovic spending the remainder of his career with United, since he got him on free transfer from Paris.
The former Sweden international has already been a big hit with the Old Trafford, scoring 16 times in 25 matches.
Ibrahimovic had been linked with leaving England for either the USA or China, before picking United.
He said, as quoted by Sky Sports: “I’m really happy for him. Maybe some people thought he was a top scorer but not anymore at 35 years old. But for him, 35 is the same as 25, Ligue 1 is the same as the Premier League.
“He scores goals, he plays well and I’m really happy for him because he will end his career on a high, which is amazing. He’s not ending his career in America or in China, he’s ending his career at the top of the top.
“I’m really pleased with him. His record is good and he can improve. With no penalties, which is amazing too because normally the other guys that are top scorers around the world, they score a lot of penalties. He has had one penalty in 17 Premier League matches so I couldn’t be happier.”
Mourinho also suggested that he thinks Ibrahimovic is a better player now than when he previously managed the Swede.
The former Chelsea boss won the Serie A title with Ibrahimovic at Inter in 2009 although says he prefers the player he is coaching now at Manchester United.
He told SFR Sport: “What he does is phenomenal. He is not just about goals, he is about the passion he brings to training sessions.
“With me, I keep saying that I had him when he was 25, 26 years old, maybe 27. Now I have him in the last period of his career and I prefer this player.”