Leandro Trossard scored the only goal from a corner-kick after some quick interchanges in the box.
To achieve this, the Gunners made use of a new routine. "There are ways, different ways to attack, different ways to try to take advantage of an opponent’s weaknesses," Mikel Arteta said.
"And obviously, they are really strong in the box and you need alternatives and we found a way to open it up."
This system involves an Arsenal player passing the corner kick short to a teammate who then finds another and another in quick succession.
To do this effectively, Arteta's men have to flood their opponent's box. The only disadvantage, however, is that they could be caught with a counterattack.