What was the hardest decision Sir Alex made?

Sir Alex Ferguson's legendary ruthless streak, and single-minded leadership policy, allowed him to make some incredibly tough decisions about his players during his time at Manchester United manager.

Twenty years ago, he signed Ji-sung Park from PSV Eindhoven and later, reflecting on the impact of the South Korean, confessed leaving him out of the matchday squad for the 2008 Champions League final, against Chelsea in Moscow, was one of the hardest, and harshest, choices he took while in charge.

But there were plenty more that will have had him agonising at the time and wondering if he was following the right path.

Not just excluding players from big matches but also discarding them altogether, agreeing to sell some of the sport's biggest names in moves that puzzled and angered some supporters. However, we all know now that history shows he got things right and was absolutely justified to be so strong in his convictions.

We've selected some of the biggest calls he made - vote in our poll to decide which, you feel, must have been the hardest...

JIM LEIGHTON (1990)

The Scotland keeper had been so close to his manager, after they were together at Aberdeen and, of course, when Ferguson took charge of the national team at the 1986 World Cup. However, a worrying run of form culminated with shipping three goals to Crystal Palace in the 1990 FA Cup final and led to the boss taking the extraordinary decision to replace Leighton with on-loan Les Sealey for the replay.

It was only the Londoner's third game for the club but he kept a clean sheet in a 1-0 win and Ferguson was vindicated in bringing home his first trophy as Reds manager. Leighton famously not only never kept goal for us again but has not spoken to his fellow countryman since.

BRYAN ROBSON (1994)

Robbo was Mr Manchester United after such distinguished service since joining the club in 1981 for a British record fee. Although the midfielder was 37 and had reached veteran status, he had lifted the Premier League trophy twice in successive years and was expecting to be on the bench for the FA Cup final against Chelsea, as the Reds chased a first Double. Ferguson showed there was no room for sentiment by electing for Lee Sharpe and Brian McClair instead, describing it as one of his most challenging selections. 

We won 4-0, with McClair scoring the final goal, and Robson left to join Middlesbrough as player-manager without getting that extra-special ending he deserved.

MARK HUGHES, PAUL INCE & ANDREI KANCHELSKIS (1995)

A number of fans felt Ferguson had lost leave of his senses when sanctioning the sale of three crowd favourites in the shape of striker Hughes, midfield marauder Ince and flying winger Kanchelskis.

Ince had become one of the best players in the division but joined Internazionale in Italy, while Hughes (Chelsea) and Kanchelskis (Everton) remained in the top flight to perhaps make matters worse and increase the risk factor. The Manchester Evening News even ran a poll asking if the manager should be sacked, which he was understandably less than pleased about, and, surprise, surprise, he knew better than anyone about the composition of his squad.

It freed up space for the Class of '92 to emerge with devastating effect and, contrary to being unable to win anything with kids, a second Double was secured the following summer.

JAAP STAM (2001)

The big Dutch man signed from PSV Eindhoven to be the rock at the back during the Treble season. Universally acknowledged as a world-class performer, it came as a massive shock when he was sold to Serie A side Lazio, a devastating bolt out of the blue.

Stam had written an autobiography entitled 'Head to Head' which reportedly upset Sir Alex, particularly as it lifted the lids on some of the secrets of the inner sanctum of the dressing room and betrayed some trust. 

Nonetheless, it was a hugely controversial call, particularly with veteran centre-back Laurent Blanc coming in as the replacement, and one that some Reds still complain about to this day.

DAVID BECKHAM (2003)

Another decision that left many a Reds follower heartbroken as one of our favourite sons was shipped out to Real Madrid, when many would have expected him to stay at Old Trafford for most, if not all, of his career.

The midfielder's celebrity status had soared to unprecedented levels, which presumably made managing a squad more difficult, and you only had to see the hullabaloo around the England international simply having a new haircut to sense his manager was losing patience. Warning signs were flashing when he was left on the bench for a key Champions League game against Real, only to come on and score twice, and, after being openly targeted by Barcelona, he instead joined their biggest rivals. 

Just as Becks had more than made up for the loss of Kanchelskis on the right flank, the new Portuguese kid coming in to fill the gap thankfully did not do too badly either.

ROY KEANE (2005)

The inspirational skipper had given his all for the club and, by his own admission, put his body on the line for the cause. It was difficult for any United fan to think about him leaving and, when he did, it came so abruptly and with the sort of explosion that one supposes could have been expected of the firebrand midfield colossus. Following a spot on 'Play the Pundit', the MUTV series that analysed performances, it was a show that never aired, reputedly due to the nature of the criticism of his team-mates for a poor display against Middlesbrough.

The brilliant Irishman later acknowledged this was not the sole reasoning behind his exit, feeling there was a recognition he needed replacing in the engine room, but it was a divisive move that saw him depart for Celtic, even if he did later get granted a testimonial, in appreciation of his extraordinary contribution to our success.

RUUD VAN NISTELROOY (2006)

At the end of that season, the deadly Dutch striker was also deemed surplus to requirements and left, after being particularly upset to be left stewing on the bench for the League Cup final win over Wigan Athletic. Rowing with Sir Alex is never probably a good idea and there was a cloud hanging over him as his goal-laden Old Trafford career edged towards an acrimonious end.

Four years later, Ruud contacted his former manager to bury the hatchet and make up but the loss of one of our all-time great scorers was tough to take, coming at the end of the season when Keane had also exited. The hitman is simply one of those footballers who fans never wanted to see leave, with him joining Beckham at the Bernabeu leaving another bitter taste.

JI-SUNG PARK (2008)

The South Korea international was such a dependable and loyal servant that it hurt Ferguson immensely to leave him out of the squad altogether for the date with destiny in Moscow, in 2008, when United conquered the cream of Europe for a third time in our history.

Park could not believe he was not even on the bench, having played such a key role in helping the Reds reach the final against Chelsea, and struggled to watch the first part of the game, such was his sorrow and anguish.

Sir Alex later told MUTV it was definitely a regret of his, even though the midfielder himself suggested it was hard to argue against, considering we won the penalty shootout in the Russian rain.

DIMITAR BERBATOV (2011)

Another Champions League final and another decision to drop an influential performer. Berbatov's artistry was made for the big stage but, as we took on football's equivalent of the Harlem Globetrotters in Pep Guardiola's brilliant Barcelona side, there was no place for the silky Bulgarian at Wembley.

Berba was the Premier League's joint-top scorer as we won another title and, if he could not be accommodated in the line-up, there was every expectation he would at least be an option to come on, at some stage of proceedings.

Javier Hernandez was preferred by Sir Alex, alongside scorer Wayne Rooney, with Michael Owen named on the bench. Berbatov revealed his boss admitted the tough choice was “killing him” and it convinced the Scot to lobby for more substitutes to be allowed in major finals.