Sir Alex Ferguson likes nothing more than a rough diamond at Manchester United.

While the Scot has purchased his fair share of big-money superstars, he has also raised plenty of eyebrows with some buys that have had United fans scratching their heads.

Some have been massive successes, Peter Schmeichel and Ole Gunnar Solskjaer being prime examples. But for every Solskjaer, there's a Bellion.

Gabriel Obertan is the most recent head-scratcher, with the player himself admitting he was stunned to find himself the subject of Ferguson's admiration.

Whether the Frenchman will go on to be a hit at Old Trafford remains to be seen. But here, Ian Watson gives his run-down of Ferguson's top five maverick misses in the transfer market.

5 - William Prunier:

Prunier never actually signed for United but his sheer awfulness sees him creep in at number five. With United facing a defensive injury crisis over Christmas in 1995, Ferguson drafted in the French centre-back on trial and was forced to throw him straight into the side. Against QPR, the 29-year-old looked relatively comfortable as he sauntered through a 2-1 win, and the ropiest of ropey chants, 'Ooh-Er-Prunier', was given an airing at Old Trafford for the first time. And last.

A couple of days later came Prunier's first real test, which he failed pretty spectacularly. United were handed a 4-1 thumping at White Hart Lane by Tottenham, for which Prunier was made a scapegoat.

Ferguson, obviously unconvinced by what he had seen, offered Prunier an extension to his trial, which the former Bordeaux stopper rejected in favour of a move to FC Copenhagen.

4 - Kleberson:

You might think that signing a player who had won the World Cup with Brazil is as close to a sure-thing as is possible in the transfer market. Well, Kleberson proves you'd be wrong.

A year after lifting the World Cup in Japan, Ferguson swooped for the midfielder, beating off competition from other Premier League clubs to complete a £6.5million deal. The fact that Leeds had previously failed to sign the Brazilian because he had no wish to leave his homeland without his 15-year-old fiancée should perhaps have acted as a sign of the farce to come during his 25-game, two-year stay at United.

The rumour goes that United actually signed the wrong player. The Red Devils reportedly thought they were buying someone who could play on the right-side of midfield, but were stunned to discover from Kleberson that he had never actually occupied in that position. Seemingly United had identified the wrong Brazilian.

Unsubstantiated rumour though it may be, the World Cup winner's form at Old Trafford certainly suggests that United's scouts got something badly wrong, and not for the first time.

3 - Eric Djemba-Djemba

Joining Kleberson in coming through the Old Trafford entrance in the summer of 2003 was Eric Djemba-Djemba.

The combatitive midfielder was identified by Ferguson as a potential successor to Roy Keane but in his two years at Old Trafford, the Cameroonian succeeded in very little.

Djemba-Djemba could run and occasionally tackle. Usually a lot later than was required but he got there eventually, bless him. However, with poor passing and abysmal shooting, he was never going to hold down a place in the United engine room, let alone replace the most influential central midfielder to play in the Premier League.

He was sold on to Aston Villa, where he faired no better, failing to break into what was at the time, a very ordinary Villa side. The Villans promptly shipped him out on loan to Burnley, and Djemba-Djemba can now be found, running around a lot and giving the ball away for Odense in Denmark.

2 - Ralph Milne:

Left-winger Ralph Milne is the player who Ferguson himself admits has been his biggest failure at Old Trafford.

Ferguson brought the Scot to United two years after the manager had moved south of the border himself. The former Dundee United midfielder was purchased to provide the ammunition for Mark Hughes and Brian McClair but instead of causing problems for opposition defences with his wing play, Milne's crosses more often had the Old Trafford faithful ducking for cover.

Milne may not have resembled George Best on the pitch but he tried his hardest to off it, more than holding his own in a United squad who were known for their drinking prowess. But whereas the likes of Robson and Whiteside were comfortable burning the candle at both ends, Milne simply couldn't.

It was his failure to change Milne's ways that Ferguson regrets most. The United boss said: "If I had an outstanding failure then it was Ralph Milne. He had tremendous talent - and I failed with him. He did not have the right attitude to the game and I could not instill that into him."

After finally giving up on Milne, Ferguson sent him to West Ham on loan, where he again failed miserably. Milne left United permanently, joining Sing Tao in Hong Kong.

1 - Massimo Taibi:

Prior to the signing of Edwin van der Sar, replacing Peter Schmeichel proved to be a major headache for Ferguson.

Mark Bosnich came in as the Great Dane's immediate successor but once his lack of fitness and discipline became clear, Ferguson looked to the continent where he found a previously unheard of Italian by the name of Massimo Taibi.

Signed for £4.4million from Venezia, the 29-year-old stopper was thrown in at the deep end at Anfield, where United fans were treated to the best and worst of Taibi in a 3-2 win over Liverpool. That was as good as it got though as two games later, Taibi made certain he would be featured on every bloopers compilation for the rest of time.

With United struggling to see off a stubborn Southampton side at Old Trafford, Matt Le Lissier carried the ball forward before scuffing a 25-yard shot towards goal. The Saints legend, so disgusted with his effort, turned away so he didn't have the pleasure of seeing Taibi allow the ball to slip through his fingers, body and legs and into the back of the net.

Ferguson, rarely one to admit he has made a mistake, gave the 'Blind Venetian' another chance when the Red Devils travelled to Chelsea in their next game. A 5-0 reverse at Stamford Bridge, though, ensured Taibi never pulled on a United shirt again.