Sir Alex believes his side are better equipped to win the Champions League again than the Reds were in 1999.
United’s Treble season brought unparalleled success to Old Trafford, but the English and European Double last term puts the Reds in a similar position this season.
"The year after 1999 we were very naïve," admitted the boss. "Teams sussed us out tactically; teams like Ajax and Anderlecht played counter-attack on their own grounds which caught us by surprise. We should have changed, but we didn’t and we suffered. We didn’t do well that year.
"This season I think I have a better squad so we can make changes tactically and we have improved that side of our game. Our players have grown up in European football. They’ve become familiar in the way the games can change in Europe."
United’s task of winning the Champions League is made harder this season by the precedent of no team winning back-to-back titles since the competition’s reformatting in 1992.
"Milan should have won it twice in a row recently, but the main reason that it’s so difficult to win it two years running is that it’s so competitive. You have the best four teams from Spain, Italy and England – it’s a very tough competition. That’s the main reason why a team hasn’t won it twice in a row in its current format."
Sir Alex puts Barcelona in with the other three English sides as the teams most likely to contest United’s European crown.
"Barcelona will be a big threat to everyone," he said. "Our experience of playing against them last season was that they are a very difficult team to play against. This season under their new coach Josep Guardiola, they have brought in Daniel Alves and one of my former players, Gerard Pique.
"They’ve changed the format of their team around and their goals against record this season is much better than it was last season. I think the natural threat to us is Barcelona. But I’ve said in the last two or three years, the English sides have established themselves as a consistent threat to all the other teams."
However, before attentions can turn to winning the competition, the Reds must first get past the hurdle of Group E. Standing in the way on Tuesday night is Villarreal, a team Sir Alex has huge respect for. Chilean coach Manuel Pellegrini has been likened to Sir Alex for the way he has gradually built a team with El Submarino Amarillo (the yellow submarines).
"He’s not as good looking as me," Sir Alex joked with the Spanish press. “The man himself is an example of how a coach can build a team with very little resources. He has created his own identity with his team. You get that with managers like Arsene Wenger at Arsenal, Brian Clough did it at Nottingham Forest and I’ve tried to do it with United. Pellegrini has established himself in this team."
It’s surprising, then, that given the attacking talent on show for both sides that three meetings in recent seasons have all ended in 0-0 draws.
"I don’t think there is any particular reason," adds the boss. "I think that Villarreal have shown what a tremendous side they are over the years. They’ve been second in La Liga twice in the last few years. To do that with a team from a small town, certainly without the resources of Barcelona, Real Madrid or Valencia, has been fantastic. They’re fantastically consistent and we know that we are playing a well-organised side on Tuesday night."