Patrice Evra
The Frenchman signed from Monaco in a £5.5 million deal back in 2006 but was soon in for a barrage of criticism after a woeful debut performance against Manchester City.
United lost the game 3-1 and Evra was substituted after just 45 "awkward" minutes. The Daily Express called it a "defensive shambles", the News of the World said his "positioning was terrible, a disaster" and The Sunday Times asked whether it was "the worst debut Evra?" Four Premier League and a Champions League winners medal in the five years since suggests not.
Nemanja Vidic
The Times declared in 2006 that United "look set for a transitional period" after they had secured the signature of Vidic in the January transfer window. The Serb crumbled as United went down 4-3 at Ewood Park, and both he and Evra were seen as temporary defensive stop-gaps at £12m for the pair.
Five years on and club captain Vidic guided his side to a record-breaking 19th league title and yet another Champions League Final. The stop-gap has become without question one of the world's most established and commanding centre-backs.
Peter Schmeichel
A chilly Autumn night and a 1-0 defeat to Vinnie Jones' Wimbledon brought Schmeichel crashing down to earth after he had arrived at United with CV which included successive "World's Best Goalkeeper" awards from the IFFHS (International Federation of Football History and Statistics) in both 1992 and 1993.
Then, when United squandered a 3-0 lead to draw 3-3 with Liverpool in 1994, he and Ferguson had a furious row which led to Schmeichel being axed from the team. A sheepish apology from the Great Dane meant that he was called back into the squad and from then on he became a true United icon. In 2000 Ferguson called his £530,000 initial transfer fee "the bargain of the century."
Andy Cole
Goal King Cole was just 23 when Ferguson spent a record £6.25 million to grab him from Newcastle in 1995, and had an "indifferent debut" according to the man from The Sun, which prompted even his manager to declare that he "isn't a miracle man."
Leeds legend Allan Clarke was slightly less forgiving and declared that Cole's "awareness, touch and passing are not up to scratch." The Sun branded him a "huge gamble" who cut "a lonely, almost isolated figure" whose "legs were jelly, the head was a whirl of good intentions confused by poor response".
Naysayers would have had very little to say in response to what happened next though. Cole netted 5 times as United obliterated Ipswich Town 9-0 and proceeded to score nearly a goal every other game over his Old Trafford career - a feat unseen since the golden era of Denis Law.
Cristiano Ronaldo
'Christiano Ronaldo' - so read a mis-spelt United team sheet shortly after the arrival of the Portuguese teen on these shores in 2003.
Ronaldo wanted to wear the number 28 at Old Trafford because he was scared he would never live up to the Reds' number 7 geniuses of the past like Best, Cantona and Beckham.
At first it seemed he was right to be so humble: he struggled against Wolves in an early game and Paul Ince warned Ferguson that he "shouldn't take liberties" by playing such unknown players against him.
According to one journalist at the time, Ronaldo "tried too hard to impress every time he touched the ball and his theatrical showboating came to nothing".
But Ronnie finished the season by scoring the opening goal in United's 3-0 win over Millwall in the FA Cup Final, and went on to become the team's poster boy before sealing an £80m move to Real Madrid after six trophy-laden years at Old Trafford.
Sir Alex Ferguson
When United lost 5-1 to Manchester City in December 1989, some fans pinned up a banner at Old Trafford that read: "Three years of excuses and it's still crap...ta-ra Fergie".
The Scot himself has since described that match as "the darkest period I have ever suffered in the game."
Fergie's tenure at United may now be seen as a masterclass in top flight management but there was a time when even he was thought to be close to the sack. The squad were plagued with drinking problems and poor fitness when he arrived and legend has it that he only saved his job by winning the FA Cup in 1990.
After an avalanche of trophies since that first FA Cup triumph it's safe to say he repaid his board's faith him many times over.
