Atletico is well capable of shutting down Madrid to 4-5 serious chances in the final. If Oblak is on a great day, and he usually is this days, I can see a 1-0, 2-1 win for Atletico. Due to the way Simeone's team play, they always create the fewer chances, but the ones they create are usually 1vs1 with the keeper. Also, the way they defend, the opponent is rarely in such a situation. They basically absorb pressure knowing that one - two -thre big chances will come for them on the counter, and knowing that such a defensive setup as the one they use will give the opponent several half-chances, but not many clear ones.
If Madrid do not play above everything they've shown so far in the season, they will probably lose. Atletico - Barca 2-0 and Atletico - Bayern 1-0 is a higher level of football than Madrid has played so far in this season, and I'm including here the Wolfsburg home game.