PSG will play Aston Villa and even though Unai Emery's side are not as consistent as one might like in the EPL, they still got what it takes to cause trouble for Luis Enrique's men and their hopes of going far.
Unai Emery is not a stranger to competitions like this and as such will prepare his boys to expect any thing from PSG especially as they may have seen how the French giants dealt with Liverpool who are the table toppers in the EPL so it will be his fault if Villa don't present a challenge to them.
Another thing that may happen is that PSG may be too focused on winning the game and forget some key areas like their defense and although I trust Gianluigi Donnarumma between the sticks but if his defense don't play their part, Aston Villa can take advantage.
PSG is in high confidence after successfully eliminating Liverpool but PSG's consistency this season has not been tested so I think there is still a possibility for Aston Villa to beat PSG in the quarter-finals later.
Overall, I think the strength of Aston Villa and PSG is not much different so it is possible for this match to be fierce.
Regarding concentration and priority, of course all teams will focus on the Champion League match because this competition is the main target of every team, especially PSG who are now only focusing on the UCL competition after they are comfortable enough at the top of the league 1 standings without any pressure to defend the title.