Arsenal boss Mikel Arteta says the way his side lost their Premier League game at Brighton is "unacceptable".
The Gunners were the better side for much of the game but threw away a one-goal lead, given to them Nicolas Pepe with just over 20 minutes remaining.
Poor defending allowed Lewis Dunk to equalise before Neal Maupay scored the winner for Brighton in the fifth minute of added time.
"I know we have a young squad but we threw the game away," said Arteta.
"I am very frustrated. It is unacceptable the way we lost the game. We had to put it to bed earlier."
The Gunners have now lost back-to-back games, with the defeat in Sussex coming after last Wednesday's shambolic 3-0 defeat at Manchester City.
A calamitous display from defender David Luiz was at the heart of the loss at the Etihad and while Saturday's performance was less disastrous, it still contained costly errors - most significantly the hesitant defending that allowed Dunk to equalise.
Arteta's side had gone into the Premier League's suspension, brought about by coronavirus pandemic, unbeaten in 2020 and with hopes of making a late charge for a Champions League spot, but this now looks unlikely, with eight points separating them and the top four.
"There's a lot of things they have gone really well but we don't compete," continued Arteta. "At this level you cannot give those sort of goals away.
"This is the challenge we all have at the football club, to rebuild to something that is worth the club we are representing.
"I just worry about tomorrow and lifting the players and winning the next football game."
In another blow to the Gunners, they also lost goalkeeper Bernd Leno to injury after he landed awkwardly following an aerial dual with Maupay.
He is the third Arsenal player to suffer an injury since the restart, with defender Pablo Mari and midfielder Granit Xhaka both carried off against City.
Maupay's challenge prompted an angry reaction from some of the Gunners team, but Arteta refused to blame the Frenchman for the injury.
"I think it was very unfortunate," added Arteta. "I don't think he wanted to hurt him, but it is not looking good [for Leno]."