That loss to Leverkusen

I was watching highlights of some past United matches and came across this match in 01-02 where we lost in sf to them on away goals. Although we were shakey defensively and that Leverkusen side were good but I feel (from the highlights) we should have progressed to the finals and played Madrid.

Now granted I was too young to be an avid football follower back then, so wanted to know the gravity of that loss back then. I know we weren't that great that season considering we finished 3rd but...

That loss to Leverkusen