The game was level at 1-1 at half-time after goals from Ousmane Dembele and Antonio Sarabia which saw Ronald Koeman bring on Lionel Messi.
The captain had surprisingly been left out of the starting XI but came on and helped turn the game around. He scored twice, was unlucky not to bag a hat-trick, and also produced a brilliant dummy to tee up Antoine Griezmann.
Alba acknowledged the captain’s contribution and admitted his team looked far better with the 33-year-old on the pitch.
“We could gone to the break with a bigger margin in terms of the lead. We have to give a lot of credit to Betis, even with 10 they played very well. I think we could have been very far ahead at half-time if we had taken our chances, but that’s the way football is sometimes.
“We know how important full-backs are for Barca’s play, they have been for many years. We have the freedom to enjoy the attack. Sometimes when you play with teams who defend in numbers you need the full-backs to help. We are better defensively, we are compact as a team. But we have to improve because we are in a league where every team can create problems.
“The quality is there. The entire squad prefers Messi on the pitch because he gives you more options to win. He came on and changed the game. We were a different team with Messi on the pitch.”
Griezmann and Pedri were also on target for the hosts in what was an important win after a run of four games without a victory. Next up is the international break which means Barca don’t play again until they take on Atletico Madrid on November 21.