Pochettino is currently having to reorganise the entire PSG side behind him because him and Messi do nothing without the ball. They just stand up front waiting to have the ball given to them. They don't move, they don't press, they don't get stuck in. Sure, with the ball, the sacrifice is probably necessary, but they're the antithesis of Pep's methods and systems, where the team defends as a unit from the front and relies on the constant tracking of runners and pressing up on the opposition defence to stop a move developing.