~Snip~
That of Aston Villa reaching the quarter finals is not luck, because they humiliated the club that they played with in the round of 16. A narrow escape is what is called luck. Liverpool winning PSG in the first leg was based on luck. PSG qualifying through penalty and Real Madrid are what we consider as luck. You shouldn't also use the performance of a team in her domestic league to judge their performance in European competition.
Aston villa's qualification to the next round of the UCL has nothing to do with luck, they have been very deliberate in their approach towards all the matches they have played this season in the Champions League, especially in the preliminary stages where they succeeded in upsetting big teams like Juventus and Bayern Munich respectively, even in the knockout stage against club Brugge, they were able to subdue the Belgian side that eliminated Atalanta and this shows how competitive they can be and I wouldn't call it luck because their game is well defined unlike Real that escaped being eliminated by Athletico Madrid after a penalty shootout.