Former United defender praises Red Devils manager, comparing him to current boss Pep Guardiola, and says 'world class' Wayne Rooney could have a big impact in the final
Pique, who spent four years at United as a youngster, has hailed the amount of silverware the Scot has won in his career.
He was quoted as saying by The Mirror: "Sir Alex is always 'The Boss' and always will be. He's absolutely incredible. He's won loads of titles and has made Manchester United the best team in England."
Though the defender played very few times for Ferguson's side before returning to the club he supported as a boy, he still feels the Scot had a big impact on his career.
He continued: "Although I didn't play a lot, I had a good relationship with him. He was always very direct with me. With Sir Alex we talked openly, and I never had a problem.
"It was a difficult time and there were hard moments when you don't understand why you're not playing. But they had two great central defenders in Rio Ferdinand and Nemanja Vidic, so it was tough for me to get a chance.
"I went there when I was 17 and came back when I was 21. The Gerard who went was very different to the one who came back."
The Catalan star also compared Ferguson with his current boss Pep Guardiola, who has won nine trophies in his three seasons as a manager.
He said: "Both of them are great motivators. All coaches know something about football - some more, some less - but it's all about how to motivate the player, knowing how to transmit what you want from them. If you compare them with each other they have many things in common."
Ahead of Saturday's showdown, the World Cup-winning centre-back also has kind words for his former team-mate and friend Wayne Rooney.
"I have never seen a player as powerful as Wayne," said Pique of the former Everton forward.
"You look at his game and you see the way he goes past people, the intensity of his play, the runs he makes from the first minute to the last and the shot that he has.
"He is simply world class and this time, unlike Rome, where he played on the left, he will be a striker and therefore more dangerous.
"Wayne is always a striker at heart and one of the best, as he always scores a lot of goals. We will have to be really concentrated not to give him space, not to give him time. Otherwise he will hurt us."