Arsenal produced a supremely professional performance to defeat Luton after making five change to the team that started their goalless draw at the Etihad.
That result had opened the door for Liverpool to climb to the Premier League summit but Mikel Arteta's side looked determined to reclaim their spot at the top.
Martin Odegaard opened the scoring with a precise strike from the edge of the area which arrowed into the bottom of Thomas Kaminski's net.
One became two before the interval when Hatters defender Daiki Hashioka turned into his own net and, despite a spirited second-half display, there was no coming back for Rob Edwards' team.