As I expected, his reasoning for the Mendy substitution defies logic.
We need to add more energy. I could take off our best option currently available to us in defensive midfield, which would make us vulnerable defensively through the middle of the pitch and add nothing to our attack. Or I could not disrupt the midfield. And instead to add energy I could freshen up the attack. How could I do that? Well I could take off the guy who has been completely ineffectual since the kick-off playing on the right wing, and being on one of the two RIGHT WINGERS I have left on the bench. And oh yeah, one of them might actually be able to cross the ball to the target man striker I brought on earlier. Yeah, easy decision, **** with the midfield.