The 34-year-old midfielder came off the bench and promptly set the tempo of the game, winning a penalty that he converted himself to make it 2-1, and drawing out a performance that showed he remains capable of influencing matches at the highest level when his body allows it.
Betis arrived having already secured their La Liga finish, and Isco reflected on the occasion with a mix of satisfaction and realism.
"Yes, both sides had already achieved their objective, but it was a beautiful game with chances. A shame about the result — when it was 2-1 we had chances to equalise but it wasn't to be."
He acknowledged the goal conceded for Barcelona's opener, a finish from João Cancelo following a costly error in their own half.
"It came from our own mistake in our half and against teams like this, if you make errors they tend to punish you. Even so, the team proposed more football in the second half and we had chances to add more goals."
Isco was asked what he said to Lamine Yamal during the match, given the symbolism of a player from his hometown city of Marbella following a path he helped inspire.
"Nothing, things you talk about on the pitch. I congratulated him on the league title and asked how he was."
He was candid about the physical challenges he has faced across a season that has been interrupted repeatedly by injury.
"I am finishing the season in much better shape than I started it and much worse than I would like. But now comes a process where I have to go step by step, try to pick up good sensations, recover my rhythm, try to get rid of the pain and hopefully return next season at my maximum level and without pain, which is the most important thing."