"We said immediately after the game 'now we need to win it'," Robben, who curled home Bayern's first in the 3-0 win at the Nou Camp on Wednesday, said in a post-match TV interview.
"Our aim is to win it this time. We have played a superb season, and tonight again. Now we have to complete it on the 25th.
"We have to stay calm," he added ahead of the first all German final against Borussia Dortmund on May 25. "At this moment we are playing great football and we have to enjoy this. But we have to try to improve over and over again.
"We are in the final for the third time in four years but it's time to win it now. It's going to be a big one. Dortmund have proved they are a very good team."
Bayern were beaten by Chelsea on penalties on home turf in last year's final and suffered a defeat by Jose Mourinho's Inter Milan side in the 2010 final but have the chance to make up for those disappointments against rivals Dortmund.
While Bayern were ruthless in both legs, Barca were a pale imitation of the side that beat Manchester United at Wembley in the 2011 final with Lionel Messi almost anonymous in the first leg and on the bench for the Nou Camp return.
"My team was very focused," Bayern manager Jupp Heynckes said. "We knew what we were up against. We played an outstanding game but there is a difference of Barca with and without Messi.
"But still it is a result one could not forecast."
Barca's Gerard Pique, who scored an own goal, said it had been a humbling night as Barca suffered their worst aggregate defeat in Europe.
"It isn't very nice to have to experience something like this," he told Canal Plus.
"I think we played a good first half but once they scored the first goal it knocked our morale. When a team is so superior you have to congratulate them.
"It obviously isn't the same to play without the best player in the world. We tried to score an early goal but I don't think that whether Leo played or not influenced the result."
Barca's president Sandro Rosell was gracious in defeat, saying Bayern were the outstanding team in Europe.
"I want to congratulate Bayern," he said. "They were clearly superior to us. They deserve to be in Wembley.
"I think Bayern are the strongest team in Europe, but anything can happen in the final."