In big games you need big players to step up.
Stones, Walker, KDB, Aguero were all missing in action tonight.
Aguero managed to miss 3 great chances, which he's been doing all season, and if Pep is serious about mistakes in the box not being good enough then he needs to sort that out.
Stones is frankly pathetic, and it wasn't surprising that Walker was going ballistic at him 5 minutes in, but would have been more convincing coming from a player who'd shown up himself.