He has come close before, including hitting the bar against Granda in the Copa del Rey, but this was a special moment for him and Barcelona.
It kept them in form, having won six in a row in La Liga, now seven points behind Atletico, although the Madrid side have played two fewer games.
The comeback was sparked by Leo Messi and Pedri, though.
Barcelona went in 1-0 down after a bad first half, with Emerson setting up Borja Iglesias for the opener shortly before the break.
Pedri came on at half-time and Barca sparked into life, getting their goal in the 57th minute, just over two after Messi came on. He scored it.
Then he played a brilliant pass for Alba, who crossed for Griezmann for the second. Antoine didn't score it. He missed, badly, but the ball bounced in off Victor Ruiz.
The Betis defender made amends by heading in the equaliser, leaving Barca looking set to drop two points until Trincao curled home brilliantly from distance to win it.