Arsene Wenger was concerned with his side's energy level after a frustrating goalless stalemate with Blackburn.
Rovers had Steven N'Zonzi sent off for a tackle on Laurent Koscielny in the second period but were not made to pay by the Gunners.
The third successive league draw means Arsenal are now seven points off leaders Manchester United, with a game in hand, with Wenger concerned by the flat display.
He said: "It was a frustrating performance because we had no pace in our game. Overall it was a flat performance with a lack of energy level, a lack of sharpness. It was quite a big concern to see what we have seen today.
"It is difficult to identify one special thing.
"I felt we started okay and after our game became flat. Very few players looked to have the resources to put the pace up in the game.
"Part of it is down to the fact that Blackburn defended well but I don't put the majority of reasons down to that. I feel it is more down to our poor offensive performance today."
Rather than thinking of the title, the Gunners boss believes his team must first rediscover their form.
"We have to focus on our performance, not on Manchester United. Before we speak about the title I believe we have to come back to a good level of performance."
Wenger added: "I fear nothing, I am concerned about our performance today.
"I just say that before we speak about the title we have to focus on our performance level, because it was not good enough today.
"That is our first concern. After that we can see, but our performance was flat, so we have to come back to a better level."
Wenger elected to leave captain Cesc Fabregas on the bench for 58 minutes, the Spain midfielder having been out for several weeks with a hamstring problem.
"It was a difficult decision but you could see that he still has some concern," Wenger said.
"He was fit, but there was some still reluctance in his head, so I decided not to start him.
"Cesc had a few setbacks, so he did not know completely if he could play 90 minutes."