The Slovenia shot-stopper produced a man-of-the-match performance with a number of breathtaking saves to help Atletico Madrid eliminate the defending champions.
Despite conceding two goals in the game, Oblak underlined his reputation as one of the world's premier goalkeepers, having saved nine shots from the hosts.
Atletico secured a 4-2 aggregate triumph thanks to Marcos Llorente's brace and Alvaro Morata's late strike, but Simeone was quick to highlight the performance of the former Benfica man and insists he is important to them as Lionel Messi is to Barcelona.
"We have a goalkeeper who is the best in the world, no doubt," the Argentine coach said after the game.
"I have been saying that for some time.”
"It's like Barcelona who have Messi. He decides games with his attacking play; Oblak resolves them with his saves."
Llorente came from the bench to replace Diego Costa eleven minutes after the break, and the Spaniard turned out to be the Hero at Anfield.
"Llorente revolutionized the team,” the 49-year-old added.
"I'm very happy for the team and the club. It was a historic match against an extraordinary opponent with great intensity and a beautiful stadium.”
"They pushed and held, without us ever moving away from our plan and with everyone's effort we succeeded.
"It gives me an enormous joy because, although it seems simple, it's not simple to win."
