Sir Alex Ferguson didn't hesitate when naming his 'biggest regret' as Man Utd manager and he thinks about it to this day

Sir Alex Ferguson has no doubts about what the biggest regret of his Manchester United career is, and he still thinks about it today.

After winning an incredible total of 38 trophies with United, Ferguson is widely regarded as one of the greatest football managers of all time.

The Scot spent 26 seasons in charge at Old Trafford, making a name for himself due to his ruthless decision making and no nonsense attitude towards his players.

However, despite his success with United, Ferguson has admitted there is still one massive decision that he regrets nearly 17 years later.

With 13 Premier League titles and two European Cups to his name, Ferguson is the most decorated British manager ever.

But it was ahead of his second victory in the Champions League final that the United manager made what he now views as the biggest mistake in his career, leaving Park Ji-Sung out of the squad for the game.

“To win the European Cup is fantastic,’ Ferguson told MUTV.

“It was a really great bunch of players with a great attitude about them and a good, strong squad.

“My problem in the 2008 final, maybe I even regret it to this day, was I left Park Ji-Sung out completely in the final.

“He’d played such a great role and that’s the problem when you get to these finals. No player deserves to be left out of the final.”

During his s seven-year spell at Old Trafford, Park was seen as more of a squad player, but Ferguson clearly trusted him as he was called upon during several of the club's biggest matches.

Park Ji-sung and Sir Alex Ferguson enjoyed a close relationship during their time at Manchester United. (Image: Getty)

The South Korean international started and played a key role in United's semi-final match against Barcelona, yet found himself left out of the matchday squad for the final against Premier League rivals Chelsea.

United won the match 6-5 on penalties after a 1-1 draw in normal time.

Ryan Giggs, Nani and Anderson all came off the bench during the match but Park was not even among the seven substitutes.

However, if the game were to take place today, perhaps Park would have made an appearance as, after protests from Ferguson and other managers, UEFA changed the rules which to allow each team that reaches a Champions League final to name 11 subs.