Liverpool are amongst the best clubs in the European top five big leagues this season,  they'll have to step up against Real Madrid who's having too many players out injured.
Atalanta are also literally buzzing,  writing them off would be some dump decision to make, although Real Madrid won them already during the super cup earlier this season.

Salzburg would be the only club most likely to be some easy game. Brest are also buzzing during the Champions league competition.