The Gunners have slipped to fourth in the table, five points behind leaders Liverpool who they host in the third round of the FA Cup at the Emirates Stadium on Sunday.
“We were not at the level (against Fulham) and we were not good enough,” said Arteta. “I don’t think we deserved to lose but we didn’t do enough to win it.
“It affects momentum that we had. Until Christmas Day we were top of the league and six days later we are fourth.
“You can be very tempted to look at things with a microscope or take the telescope and look a little bit further ahead and treat things with a little bit more perspective.
“And my job, big time, is to look with the telescope, have perspective, analyse things in a broader way and not get affected by one performance; not results, just one performance.”
The club continue to be linked with a new striker, although Brentford manager Thomas Frank said only an “unbelievable” offer would force the Bees to sell Ivan Toney during this month’s transfer window.
“We are open to the transfer market,” added Arteta. “But the emphasis is on making the most of the players we have.
“We will work with the club and see if we have any good options but first, our focus is on the players here.”
Put to Arteta that Arsenal might not sign anyone before the window closes, he replied: “That’s a possibility.”
Arteta is likely to rotate his squad for the visit of Liverpool, with defender Oleksandr Zinchenko possibly back in the frame after missing the defeat against Fulham.
Goalkeeper Aaron Ramsdale is also set to be handed a rare start in place of David Raya.
“There is a big history between the FA Cup and the club and we have a big opportunity (against Liverpool) to start again and make a beautiful journey,” said the Gunners boss.
“We are really happy with the atmosphere that we have created at the Emirates Stadium and on Sunday can we make it even more hostile? I think we can.
“We have to be so grateful for what we are achieving in our home ground and Sunday is going to be a big one again.”