The Premier League champions made all the right noises at the start of the close season with bids for Barcelona's Cesc Fabregas and media reports of a desire to recapture Cristiano Ronaldo signalling real ambition to net a big name.
Yet as the clock ticked down on Monday's transfer deadline day, United were minutes away from coming away with only a promising Uruguayan youngster as attempts to sign Athletic Bilbao's Ander Herrera and Real Madrid's Fabio Coentrao failed.
A close season spent fighting off Chelsea's advances for disgruntled England striker Wayne Rooney was also an unnecessary distraction as each of the club's transfer targets appeared to join other clubs or opt to stay put.
In the end, they hurried through a £27.5 million deal for Everton's Fellaini, who is undoubtedly talented but does not have the same pedigree as their failed targets or Arsenal's last-minute buy Mesut Ozil.
United manager David Moyes had maintained throughout that he would not be worried if his club did not bring in any new faces as he was happy with his squad and yet the final-day chase of a number of players had a frantic air about it.
They said their pursuit of Herrera ended because they felt his buyout clause was too high while the word coming from Spain was altogether more alarming with media reports of imposters posing as United representatives trying to seal a deal.
A spokesman for the Spanish professional league (LFP) said three lawyers had gone to their offices in Madrid on Monday purporting to be representing United and after some discussions left without making the buyout clause payment.
A United spokesman said no one from the club had gone to the offices.
The English champions were also linked during the day with a late move for Real Madrid left back Coentrao but in the end their business was conducted much closer to home.
The fact Fellaini was coming from United manager David Moyes' former club Everton would suggest a deal could have been done much earlier, had he been their top choice signing, as the Scot would have known the Belgian's contract inside out.
Fellaini's arrival addresses the need for a central midfielder who can get into double figures in the goal-scoring department but it will not appease fans who have seen title rivals Manchester City, Chelsea, Tottenham Hotspur and Arsenal boost their squads with world-class talent.
"I think that's an area where everybody felt we could do with strengthening... For me, he's been one of the best midfielders in the Premier League over the last few seasons," Moyes said of the 25-year-old Belgium international.
"If he can join a club like Manchester United and continue to improve hopefully we'll have a real good player on our hands."
The trouble for Moyes is that the weight of expectation surrounding the 20-times champions means that 'hopefully' is not good enough.
Not when other members of European football's aristocracy have been bringing in the big guns such as Real Madrid's world record swoop for Spurs winger Gareth Bale and Barcelona's capture of exciting Brazil striker Neymar.
Those are the calibre of players United's fans, who took to Internet forums to express their frustration, would expect to be chasing.
A year ago, their big transfer window business was signing striker Robin van Persie, who joined from Arsenal in prolific form as one of the world's class acts rather than just English football's and for a fee three million pounds less than Fellaini's.
That deal, like most conducted under Moyes's predecessor Alex Ferguson, was completed well before deadline day - the most notable exception being the last-minute capture of Dimitar Berbatov from Tottenham Hotspur in 2008.
The club is in a period of transition with a new chief executive in Ed Woodward, succeeding the experienced David Gill, as well as a new manager and the events in this transfer window could just be teething problems as United discover it is more than just their name that is needed to attract the world's best.
All eyes, however, will be on how United perform in their title defence before they get the chance to put into practice what they have learnt when the transfer window reopens in January.
A lacklustre home draw against Chelsea and disappointing defeat at bitter rivals Liverpool in their last two league fixtures suggest that Moyes will need to string together a series of good results to get disgruntled fans back on his side.