Slovenia international Oblak showed incredible reactions to keep out a header from Enis Bardhi in the 93rd minute of the clash at the Wanda Metropolitano.
The keeper has saved 14 of the past 17 shots on target he has faced in LaLiga, including the last two against Levante.
Atletico have now won four games on the trot in all competitions and Simeone was full of praise for Oblak, although he was frustrated to have to rely on the 26-year-old after a string of wasted chances at the other end.
"For us he is the best in the world. He's one of our captains. He was there when it mattered most, but the last save was one of a player that wins you games," said Simeone.
"He gave us the possibility of winning a match that we should have finished off before.
"The headline is Oblak saved Atletico, but we would have saved it if we'd taken our chances before.
"I do not decide who wins a prize or not. It is unfair to talk about other goalkeepers, but it's clear that for us he is the best goalkeeper in the world."