Of course this always happen most times in football were a team that look more superior will end up losing against those teams that people always considered as the weak ones, this is why we can't possibly predict psg to win Aston villa just because they got liverpool eliminated. Remember Aston villa also defeat liverpool most times in there domestic league, that's to show that anything can happen in this match.
Liverpool are our because they failed to meet up the standards of PSG in the both home and away rounds. I don't see any team stopping Paris Saint-Germain from advancing to the grand finale of the UEFA Champions League this season. There have been quite important in the tournament anf giving up us not an option for the club. Luis Enrique ensured his team is stable in stellar performance, they're able to pull the big winnings and eliminating tougher oppositions. PSG are on their path to ensure they grabbed all positivity and winnings becomes imperative for their ends.
Is not like that they didn't meet up to PSG standard, they won PSG in PSG home though with hard labor and PSG beat Liverpool in Liverpool's home and Liverpool posses them so it was a 50/50 game just that they were unfortunate in the penalty kick. Saying that you don't see any team stopping PSG in the champions league is a wrong statement because the fact that they beat Liverpool doesn't mean they will beat any team they meet, I would not want to argue anyway but let see what they will play against Aston villa.