For the second time in a week, the Gunners blew a 2-0 advantage, this time allowing the Cottagers to recover and then lead after early goals from Olivier Giroud and Lukas Podolski had put the hosts in command. Mikel Arteta then saw his stoppage-time penalty saved by Fulham goalkeeper Mark Schwarzer.
Wenger knows such costly lapses in concentration at the back must be eradicated if his side are to keep within striking distance of the top four. "We were defensively fragile, were not cautious enough at 2-0 and we let them back into the game because we lacked urgency," the Arsenal manager said.
"We showed magnificent spirit in the second half, but the team has to learn to deal better with this kind of situation. There are good ingredients in this team, a good spirit, but we need a bit more defensively when we are leading the game."
Wenger added: "At the moment, we do not get the points we want. Of course, we now do not have to waste any more time, but I still feel there is good potential in our side."
Arsenal will have little time to attempt to rectify their defensive shortcomings ahead of next weekend's north London derby at home to Tottenham as nearly all of the first-team squad will be away on international duty.
One positive for Arsenal in the past few weeks has been the development of Giroud.
The France forward, signed from Montpellier in a £13million deal over the summer, now has four goals in as many appearances for the Gunners.
Wenger said: "Giroud had presence and won the long balls. He is dangerous and starts to have belief in what he is doing."
Source: PA
Source: PA