Liverpool and Manchester City aren't on the same level this season, while City have struggled for form, Liverpool have been taking the league by storm and still look set to continue, breaking numerous records on the way. And also when City played Norwich, Norwich were in good form then, but that form seem to have faded off as the season went on, so this game is a different game for the both teams.
It's going to be difficult to choose between Mane and Virgil who's the better player for Liverpool, I'll choose mane because of the number of goals he scores. If Liverpool are to beat Athletico Madrid, then Mane would have a pivotal role to play.