After a lukewarm display from both sides in the first half, Nicolas Pepe put Arsenal ahead with a sublime finish, but their lead was short-lived as defender Lewis Dunk pulled parity for the Seagulls seven minutes later.
The game was heading for a stalemate before Neal Maupay, whose collision earlier with Bernd Leno had seen the goalkeeper stretchered off, handed a mortal blow for the visitors.
In an interview with BBC Sports after the game, Arteta admitted he was livid with the result and insists it is unacceptable for the North Londoners to lose in that manner.
"I am very frustrated. It is unacceptable the way we lost the game,’ the Spanish coach said.
“We like competing and I know we have a young squad but still, we threw the game away. We had to put it to bed earlier."
Leno was stretched off in the first half after a collision with Maupay but the 37-year-old believes the Frenchman did not intend to hurt the former Bayer Leverkusen goalkeeper.
"I think it was very unfortunate. I don't think he wanted to hurt him, it is not looking good,” he added.
“We have to fight and be positive, tomorrow is a different day. I think the players that came on today did really well, we did more than enough to win the game comfortably but we leave with zero points again. “
"I think this was a very different one to the one against Manchester City, when you give cheap goals like we did in this one you will suffer."
