Arsenal manager Mikel Arteta criticised his side for not killing off 10-man Fulham as the visitors scored early and late to snatch a 2-2 draw at the Emirates on Saturday.
Andreas Pereira struck in the first minute as he pounced on a sloppy pass from Bukayo Saka to put Fulham in front.
Arteta's substitutions appeared to have turned the game as Fabio Vieira won a penalty, converted by Saka, to level before teeing up Eddie Nketiah to put Arsenal 2-1 up.
Fulham then lost Calvin Bassey to a second booking, but still hit back when Joao Palhinha took advantage of more poor defending to sweep home a corner in the 87th minute.
"We have to show another level of commitment and desire. With 10 men, you cannot concede a goal," said an irritable Arteta.
"Right from the beginning, we gave an incredible goal away. You make life really difficult for yourself, but the team reacted really well.
"We dominated the game and created countless chances and should have scored five, six, seven goals easily. And, when you have done the most difficult thing which is to get back ahead against a team that is well organised, you have to defend your box from one corner.
"It is the only chance they have and you get punished."
Arsenal are aiming to win the Premier League for the first time in 20 years after narrowly missing out to treble winners Manchester City last season.
The Gunners appear to have greater strength in depth this season after the signings of Declan Rice and Kai Havertz.
It showed as Vieira and Nketiah made telling contributions off the bench, while Oleksandr Zinchenko also impressed on his return from injury as a substitute.
"All three substitutes changed the game. Fabio was involved in everything we created and I am really happy with that," added Arteta.
"The same with Eddie. It is my fault that Fabio has not played more and today he gave me reasons to play him more."
Arsenal's first dropped points of the season saw them miss out on top spot in the Premier League to north London rivals Tottenham on goal difference.
Both sides have seven points from their opening three games, but could be usurped by City, who are in action at Sheffield United on Sunday.