Signed by United as a shy 14-year-old schoolboy, Hughes was thrust into the spotlight with goals on his debut and PFA awards within a year of his breakthrough.
Yet a stand-off over a new contract saw him pushed into a deal to join La Liga giants Barcelona, with the documentary showing the 72-cap Wales international admit he was “lying” as he watches his 22-year-old self say he was looking forward to the move to join Terry Venables’ team.
“I didn’t have that confidence to say ‘I’m not going’ and it just kept going and I found myself on a plane flying to Barcelona,” he says.
He joined ‘El Tel’s’ revolution alongside Gary Lineker, whose success was in sharp contrast to Hughes’, who struggled utilising his renowned physicality in Spanish football.
On top of that, the self-confessed introvert struggled to adapt to his new, very different, surroundings.
“That was a hard time for him,” Lineker says in the documentary. “There was a feeling perhaps back then of ‘just get on with it, you’re a big star, deal with it’.”
Hughes calls it his lowest ebb, admitting the levels of criticism from media and supporters in Spain were difficult to come to terms with.
Even a player with such a fearsome reputation concedes: “When you have 90,000 waving a white handkerchief that is a bit hard to take.
“I faced a level of criticism not a lot of players had faced at that time, certainly as a young player.”
Lineker reveals his role as an impromptu mediator to help Hughes force a way out and – after a loan spell at Bayern Munich – back to United under Ferguson in 1988.
“Fans loved him,” Ferguson says, the transfer being dubbed as the return of the prodigal son. “If I was a football fan, I’d want to see players play with the enthusiasm and determination the way Mark did.”
Beckham, who says he queued for Hughes’ autograph as a young United fan, says his knack of scoring big goals in big games is a reason why he is still revered at Old Trafford.
But Hughes laughs that not many people remember his outside of the foot pass to set up Mark Robins for the FA Cup third round goal at Nottingham Forest, the goal credited with keeping Fergie in a job.
Triumph at Wembley set up a European Cup Winners’ Cup run, and while Hughes says his memorable match-winning brace in the 1991 final against his former Spanish side was not about revenge, Ferguson acknowledges: “I think it was his pride – he was showing Barcelona exactly what they were missing.”
Legends of Welsh Sport: Mark Hughes is available to watch on BBC iPlayer and BBC One Wales from Tuesday, 7 January at 20:00 GMT and later on demand.