This one is a hard pill to swallow.
Gavi, the most hard working and aggressive player on the field, was in desperate need of being saved from himself. Instead, being left to shoot himself in the foot with his own best weapon. That one is on his coach.
The substitution was screaming out the moment Gavi picked up an early yellow card, a needed tactical follow to kill a potentially dangerous counter attack.
But Xavi never made the move, and was made to pay for it in the 80th minute as his team was looking to see out the game with a slim and critical one-goal lead.