Valencia has shown metal in Champions League especially against Chelsea and Ajax in away games. Atlanta is comparatively weaker side, IMO.
as a fan, i could add that in March/April, even Europa league this season was seen as doubtful, since Valencia was in the middle of the table, but showed strength compared to Getafe, Sevilla, Alaves, Bilbao and reached position four in last round, then reached group stage, and finally kick-out stage in the last round, kicking out last year semifinalist Ajax on their pitch, it is an amassing strike for them
Atalanta is certainly the best you can get in this stage of CL, but Valencia was first in their group after all, so deserved team from position two, and due to same country it could not be Atletico or Real Madrid, and Chelsea from the same group, that left us with names that are not that better than Atalanta
here are my predictions
Dortmund vs
PSGReal Madrid vs Manchester City
Atalanta vs
Valencia Atletico vs
LiverpoolChelsea vs -
BayernLyon vs
JuventusTottenham vs Leipzig
Napoli vs Barcelona