Neville told the 20th Anniversary edition of Red News: “There have been two or three seasons in Europe where we haven’t performed as players. Borussia Dortmund and Bayer Leverkusen – criminal, criminal those two.
“We should have been in the final those two years but were guilty of not performing, not taking our chances. There are also a number of clubs in Europe who have the history and tradition of United.
“Real Madrid, Barcelona, Bayern Munich, Juventus and AC Milan, we have to respect them. These clubs in their own country are huge clubs with massive tradition.
“I’d always say United is the biggest club but even the most ardent United fans would recognise the size of these clubs and know they are massive.
“They all have the same ambition, they all want the same thing but they don’t win it five or 10 times, apart from Real Madrid who have won it nine times.
“Since it has been the Champions League, Real Madrid have won it twice and Bayern Munich once. It’s a hard competition to win.”
He added: “I said after 1999 that I never thought it would be done again, just because I experienced what happened then. Every season since there’s been a team in that position.
“Chelsea can still win the Quadruple, Arsenal could have won the Treble one season and last season Chelsea were still in most competitions until the fifth or sixth round or the semi-finals.
“Everything just has to go your way – everything. You need an extreme amount of luck. Not just determination, winning 1-0, you need luck, genuine luck.
“We won some of those games and you couldn’t explain in words what happened. We did all the right things, we prepared well, we worked hard and we had a great spirit. But you need an extreme amount of luck and I still think it’s going to be extremely difficult to achieve, so talk of it at this stage is really premature.”
