United's cup double and second placed finish in 2016 the undisputed highlight of his five-and-half years at the club.
Fellaini, now with Shandong Luneng, told the Daily Mail: "I played five and half years for Manchester. My first season was a transition, so I was in transition, I know I didn't have a great season. But after that I played my games, played well and I won things.
"Okay, I didn't win the Premier League but that's part of football. Manchester City was a strong team and was difficult to battle against them.
"But I did some great games, scored some important goals, so for me I was very happy with my time in Manchester.' Unfortunately, Old Trafford isn't quite so cheery right now."