The Gunners' top four chances now hang in the balance as the fifth-placed Toffees bridged the gap to just one point - and a game in hand - thanks to first-half goals from Steven Naismith and Romelu Lukaku before an own-goal from old boy Mikel Arteta.
Wenger's Arsenal are now winless in their past four Premier League outings, which has their Champions League hopes in doubt, and the Frenchman was left to pick up the pieces after another shoddy performance against a top-five team.
"Everton were better than us. We were not at a good level and have to come back to basics," Wenger told Sky Sports.
"We gave away an early goal and then a second that was very easy to avoid.
"In the second half when we looked like we were coming back into the game we gave the third goal away.
"It is a very disappointing performance overall."
Wenger could offer no reason why Arsenal have been subject to heavy defeats from top three sides Liverpool, Manchester City and Chelsea recently, as well as Everton, as they now prepare for the FA Cup semi-final against Wigan Athletic next weekend.
"It is tough to say, and that cannot be used as an excuse anyway," he added.
"It is my job (to pick the players up). We go into an FA Cup semi-final and that is the target. We have to pick ourselves up and come back with a different spirit."
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