With the tie finely poised at 1-1 apiece going into the second-leg, the Catalan giants sent the Mestalla outfit packing from the Nou Camp to complete a 3-1 aggregate win thanks to goals from Cesc Fabregas and Xavi as Barca progressed to their third Cup final in four years.
"In Valencia we played an extraordinary game, and today we did it again. We generated a lot of football, with an almost infinite amount of plays. Save the first minutes of each half, when we could go at them we had the game and we didn't let it slip away," Guardiola was quoted as saying on the club's official website.
"It's a great achievement," and, at the same time, it says "a lot about the players."
"When you're tempted to doubt a player, to say that they are tired or comfortable, count to five or six and think about how some people regard this competition as the least prestigious, the one that's least valuable, we've reached the final three out of four years," he said.
Barca will pit their wits against Basque outfit Athletic Bilbao in the Copa del Rey final and Guardiola is anticipating a tasty clash between two of the competition's most successful sides.
Labeling the showpiece final as a "marvelous spectacle", Guardiola said, ""We're very excited to play against Athletic. We've happy to have another final saved away. It's a final with the teams that have the most titles in the competition."
"I believe it will be fascinating, because I haven't seen a team that plays into space like Athletic. They will come for us, and we'll do the same. It'll be a beautiful final for spectators that will give prestige to the competition."
Former Barcelona skipper Guardiola also lauded the talents of precocious midfielder Thiago and veteran custodian Jose Pinto.
"He (Thiago) had an extraordinary match, he played like a man. He audaciously played in a position that he's not used to," Guardiola mused.
"He (Pinto) was impeccable," especially with his foot work. "In four years he'll have played three finals, and that says a lot about his personality, his strength."
Looking ahead to domestic matters in La Liga, Guardiola urged his charges to maintain the momentum and try to overcome Real Madrid's seven point advantage.
"it's normal that in La Liga we're below a team like Real Madrid. We're in a tough situation in the competition," he added.
"It'll be very difficult to reach them. We have to force them to win it. We have put pressure on them. In the end, these players challenge themselves."