After a tortuous summer, the Belgium international can start preparing to make his United debut against Crystal Palace at Old Trafford on Saturday.
Although manager David Moyes knew as soon as he was appointed as Sir Alex Ferguson's successor that he wanted Fellaini to make the switch from Goodison Park with him, it was not until the last dregs of the transfer window that a £27.5million switch was finally concluded.
But now it has, Fellaini has set his sights on having an Old Trafford career to remember.
"Roy Keane was an aggressive player who could win every ball," said Fellaini. "Maybe I can do this as well.
"I can win the ball. I can clear the ball. I can play clean.
"The manager must decide where I play but I want to play defensive midfield.
"In the past they have had (Eric) Cantona, Keane, (David) Beckham. I hope (I can do it too). I will work hard for this."
United did not confirm Fellaini had become the fourth most expensive player in their history until 2am on September 3, three hours after the transfer window had closed.
Prior to that, the 25-year-old had driven back to Everton's Finch Farm training complex for one final time in order to persuade Blues manager Roberto Martinez of his desire to leave.