Arsenal manager Arsene Wenger admitted Sunday's 3-1 home defeat to Manchester United had come as a massive disappointment.
The Gunners' defending was dire as they suffered a humiliating home defeat in much the same way as they had been humbled by Chelsea earlier in the campaign.
Arsenal are five points behind leaders Chelsea and the gap could be stretched to sight points if the Blues beat Hull City in midweek.
Wenger admitted: "It is a massive blow and a massive disappointment. We need something special now to stay in the race, of course. I am conscious of that.
"But we have to recover, that is part of top-level football. It is difficult to take, but easy to explain because we were poor offensively and defensively.
"We delivered an off-the-mark performance completely and that is why we were well beaten. We gave them always too much room, we were naive.
"They were better than us for two reasons: one, they played well and two, we were not at our level.
"Why? It is too early to analyse that. I believe there are some mental reasons in there, but it is difficult to say.
"Now, we have to stick together, recover and produce a much better performance next Sunday (against Chelsea)."