The Gunners slumped to a second straight league loss at Goodison Park despite taking the lead on the cusp of halftime through Martin Odegaard.
Richarlison equalised for the hosts with eleven minutes on the clock remaining and Demarai Gray earned Rafael Benitez some much-needed reprieve with the winner in the second minute of stoppage time.
Arsenal dropped to seventh on the table and have now lost three of their last four league games.
"In the first half, we were very inconsistent with the ball," Arteta told Sky Sports. "I didn't like it. [We had] no penetration; one of the few times we did it, we scored.
"Second half, we tried to do more of those things, created four big chances, but conceded a very sloppy goal when you need to manage the game.
"I think the team tried to keep going, we kept pressing high. We lost a few important duels that put us some pressure."
"What I want is more from my team. Today, you have the game under control even though you're not playing your best, and you have to find a way to win it.
"It could have been very different, but we haven't managed to do it. When the opponent is there for the taking, you have to do it, and we haven't. It wasn't good enough."
Arsenal will host Southampton in their next league game this weekend.
