Arsenal have confirmed that a fan was arrested after throwing an object towards Manchester United's bench after the visitors' opening goal at Emirates Stadium on Saturday.
United moved back into the top four following a 2-1 win in North London, as Kieran Gibbs scored an own goal before Wayne Rooney put the game beyond the Gunners, despite Olivier Giroud's late strike.
Should Arsenal stick with Arsene Wenger as their manager?
Arsenal have promised stiff action against the fan if he is found guilty.
An Arsenal spokesman told Press Association Sport:...