Atletico won last week's semi-final first leg at their Vicente Calderon home 4-2 and when Adrian powered home a stunning goal from wide on the right on the hour at the Mestalla, Valencia's hopes of turning the tie around were crushed.
Atleti had midfielder Tiago sent off in the 79th minute after players from both sides became involved in an ugly melee and the Portuguese slapped Valencia striker Roberto Soldado across the face.
It all came too late for the home side and Atletico cruised to a 1-0 victory on the night - their 11th straight win in Europe this season - as they claimed a 5-2 aggregate success.
"I am very happy, mainly for the players, who have made an enormous effort. What they did is heroic," Simeone said.
"We knew it would be difficult and they pressured us well, which is to be expected here at the Mestalla.
"In the second half we made a tactical change and didn't suffer as many problems and we knew as time went on the spaces would open up and the goal pretty much settled the tie."
Valencia poured forward in search of an early goal to start the fightback but ran up against inspired Atletico goalkeeper Thibaut Courtois, on loan from Chelsea.
The hosts had one of their brightest performers on the night, Sergio Canales, carried off on a stretcher in tears with what looked like a serious knee injury in the 59th minute and almost immediately Adrian ended the game as a contest.
Diego sprayed the ball to the Spanish youth international wide of the area and he chested it down and struck a spectacular volley inside the far post.
"I controlled the ball and just put everything into the shot and it went in," Adrian said.
"We knew they would come out at us strongly. We knew we had to defend well and that's what we did. We withstood the pressure and in the second half we were able to win the game.
"It says a lot about Spanish football that we have two teams there and it should be a great final."
Atletico also beat Valencia in the quarter-finals in 2010 on their way to winning the competition with an extra-time 2-1 victory over Fulham in the final in Hamburg.
Looking ahead to the final in Bucharest, Simeone said: "Athletic are having a superb tournament. I can only congratulate them.
"I know Marcelo Bielsa well and also the people who work with him. It will be a nice final between friends but we want to win."