Philippe Coutinho scored his first Barcelona goal, just minutes after coming on against Valencia as a half-time substitute.
The Brazilian was dropped for the Copa del Rey semi-final second leg at Mestalla on Thursday, but came on at the break for the ineffective Andre Gomes.
And the 25-year-old made an instant impact, opening his Barcelona account in the 49th minute to give his side a 1-0 lead on the night, and a 2-0 advantage on aggregate.
Luis Suarez created the idea going on a mazy run and crossing to the back post, where Coutinho slid in and finished low across the goalkeeper into the far post.
It was the fifth appearance with Barcelona for the €160 million signing, two of which have been starts in La Liga and three of which have been substitute appearances in the Copa de Rey.
“It’s a very happy day,” Coutinho told GOL after the match. “I was looking for the goal in the first few games and today I got it and, most importantly, helped the team reach the final.
“It’s a special moment. It’ll be a great game and a difficult one [against Sevilla]. We have time to prepare ourselves.
“It’s my first final and it’s a special and important moment for me, but there are a lot of moments to play before the final.”