I think Sparta still has more motivation and chances to win the championship. Sparta is a team with a European reputation, and holding onto a result in matches of this kind should not be a first for them!
I think Atl. Madrid are capable of achieving not a miracle, but simply a victory and progressing further. Although Chelsea are currently showing consistency, in my opinion they look very shaky; there is no bright, attractive football!
I don't think Atalanta will have much freedom at the start of the game. The difference in goals after the first match is minimal, so Atalanta have a great chance to impose a fight and simply cannot afford to concede.
If Tambov can hold on in the first half through sheer willpower and physical strength, the second half will belong to Krasnodar. They will feel really uneasy if they fail to score and beat a depleted Tambov!