Atletico x Bayern
I see a very close game. The teams are like exact opposites. Atletico defends well, but does not have so much attacking threat. Although they play at home, they will probably play on the counter, and try to speculate set pieces. Atletico did not do well against the only team that has Bayern's style, namely Barcelona. Before eliminating them in the previous round, they lost 6 consecutive games against Barcelona. I think Bayern is 5-10% worse than Barcelona in attacking threat, and i think Simeone will be confident he can get away with a 0-0. I am also pretty sure that he knows Bayern is vulnerable(for this level) at set-pieces, because their central defender pair is not the best. And Atleti is maybe the best team in the world from these situations.
All these things lead me to a 0-0 at HT, which has nice odds, 2.3.