Arsene Wenger has admitted Everton's slip-up has given Arsenal “big encouragement” they can finish fourth.
Gunners boss Wenger knows his team can go four points clear of Everton in fourth if they win at Hull on Sunday.
Roberto Martinez's men entertain Manchester United later on Sunday afternoon but Everton's home defeat to Crystal Palace has let Arsenal back in the race for the top four.
Wenger said: “We are in a period of the season where every game has a big impact. We just prepare massively well for the next game and try to give your best and hope results around you go for you.
"It is, of course, a big encouragement but there's there's a lot of work to do for us. We have a big game at Hull.
“Mentally we are in better shape than a week ago because we had two important wins and that puts us in a better condition on the confidence front.'
“We wanted Crystal Palace to make a result but you know that in the Premier League it is like that. You can drop points everywhere.
“Was I surprised? Yes and no.”
Wenger revealed Kieran Gibbs is likely to miss out on the trip to Hull but Nacho Monreal should be fit.
Mesut Ozil has a chance of being and Mathieu Flamini is available after suspension.
Wenger added: “Ozil is possibly available to travel as well. Will see on Friday or Saturday.”