Manchester United legend Sir Bobby Charlton believes Sir Alex Ferguson has surpassed Sir Matt Busby as the club's greatest manager.
Charlton won the European Cup with Busby.
He told the Daily Mail: "The Old Man was the keenest judge of a young player and Alex is maintaining the tradition of us developing our own talent. The competition didn't used to be so fierce but now it's not unusual for Alex to get up at five in the morning, drive a 300-mile round trip to make sure he doesn't miss out on signing a youngster and then be back in time to take training.
"Matt didn't do the coaching like Alex does. I was taught the game by Jimmy Murphy (Busby's assistant who took a decimated United to the 1958 FA Cup final in the immediate aftermath of Munich). But he also controlled everything in his way. Both high motivators. Both great judges of character. Both profound psychologists. Both involved in every last detail.
"Between them they've built this into the biggest club in the world. Yes, bigger than Barcelona. Bigger than Real Madrid. At the last count earlier this year we had 333 million registered supporters around the world. They both get the credit.
"But no manager has ever been as decisive as Alex. He is amazingly brave with the big calls and invariably gets them right. So when it comes to tactics, thank heaven it's Alex who has to come up with the gameplan to beat Barcelona. Whatever he decides, he will give the lads their best chance of winning.
"He always does. Whatever the result - and in football nobody can win every game - not one of his teams ever comes off at the end having done itself less than justice. His mind will be so busy that he'll be staying awake nights now. He mentioned how he lost sleep before taking the gamble to leave out so many key players in the second leg of the semi-final against Schalke. He will be again, this week."