The Gunners were held to a 1-1 draw against the Seagulls as their chances of finishing in the top four took a hit.
Arsenal took the lead early as Pierre-Emerick Aubameyang converted a penalty.
But Brighton equalised from the spot themselves following a Granit Xhaka foul.
And that attack was caused by former Manchester United winger Henrikh Mkhitaryan misplacing a routine pass.
Fans immediately took to social media to tell Emery what he needs to do this summer in the transfer window.
One said: “Xhaka, Mkhitaryan and Lichtsteiner should be sold off pls.”
Another added: “Bin Mkhi and Xhaka. Had enough of them.”
“@UnaiEmery_ Xhaka is an accident waiting to happen. Don’t let him play near our penalty box and Mkhitaryan is past his best. Needs to leave in the summer,” a third explained.
One more said: “I’ve had enough of Xhaka and Mkhitaryan!”
Arsenal now trail Tottenham by three points with their rivals having a better goal difference.
That means the Gunners will play Europa League football next season unless they win the competition this campaign.
Emery’s side are in the driving seat to reach the final as they lead Valencia 3-1 after the semi-final first leg at the Emirates.
Arsenal could take on Chelsea with a place in the Champions League up for grabs.
Former Gunner Alan Smith thinks fifth or sixth is about right for this current crop of players.
He said: “I have to be brutally honest, but fifth or sixth for this Arsenal team is about right.
“If they had finished in the top four, it would have been over-achievement.
“They have good strikers but as a team they have a lot of work to do.”