It's a silly hyperbole which you keep in your mind because a barely known dude named Derlei went down a bit too easy to win a glorified corner kick. All that followed after that, a last minute loss, Mourinho's crazy celebration, and what he turned out to be means you guys in here make too much of it. At the end of the day, just a fecking free kick in the first knockout round of a CL. Far worse things have happened, including in finals, since then.
You probably barely remember much about Porto other than the game against United anyway, that would be a far too biased memory. Common anyway, I've been here far too much time and had this dumb discussion too many times.
Christ, teams like Barcelona did it far more consistently throughout seasons after seasons, just look at the discussion above... No one says it was crucial to their success.