the relative quality of all continental sides was higher back then, imo, they had all won something, Lyn Oslo may not be much now but comparatively they would have been a tougher game than FC Pigfarmer who qualified for the EL because their chairman's wife won a croquet tournament, add in the difficulties with travel, accommodation, facilities and food, which were unquestionably a greater issue back then, and the land really doesn't look that level (to me at least), there is a reason away goals used to be so highly regarded and now seem a little silly
lets not forget that they scored 3 against us in the first leg by the way, if they were good enough to put 3 past that Spurs side they must have been handy, United were the only side to better that that year