Arsenal manager Arsene Wenger has accused referee Neil Swarbrick of making a 'ridiculous and scandalous' decision by awarding Watford a penalty in his side's 2-1 defeat.
Replays suggest that Wenger was right to be unhappy with the call, however, which would prove costly for the Gunners as Troy Deeney tucked away from the spot before Tom Cleverley scored an injury-time winner.
Speaking to reporters after the match, Wenger said: "The decision on the penalty is a bit ridiculous and then we panicked a bit for their second goal and in the end we stand with a defeat.
"It is a scandalous decision, but what can we do about it? Nothing. We can talk and talk and talk. At the end of the day they scored. It was not a penalty, it was a creation of the referee. The decision is wrong and that's it. And it came at an absolutely important time for them. No penalty, no goal.
"I think our level dropped in the second half and we missed many chances to kill the game. After that, at 1-1, there was no need to panic. I believe that on the second goal we can only look at ourselves."
Arsenal last lost a league game to a 90th-minute goal in January 2012 when Bobby Zamora netted for London rivals Fulham.