Having been away with Chile during the week, Sanchez started on the bench, but with the game at 2-1, Guardiola decided to throw on the midfielder.
However, when sprinting for the ball, Sanchez pulled up with an apparent groin injury. Guardiola was seen kicking the turf on the touchline and when Sanchez came off he said: "Use your head."
Guardiola is unhappy with the way Sanchez is managing his fitness and afterwards remarked: "He's very young, only 22 years old and a young and eager player will always try to please you when he can. He'll learn from this. I'm sure he will learn from this injury."