The Gunners have not made the start that fans were expecting, as they are nine points behind Liverpool in the title race.
While they are only four behind Manchester City, the gap to the Reds means the title may be out of reach at present.
"The season hasn't started as we expect them to," Gilberto admitted to The Mirror ahead of his Strive Aid charity match against Team Roberto Carlos.
"The last few years have been so nice. They have done well fighting for the title.
“And then we expect them to have a great start. But it's not the end of the world. There's a lot of games to be played."
"The question is about recovering the points and not losing silly points," the 48-year-old added.
"Because it's going to be a tough season again. Not only against City, but Liverpool is back.
"And then we have other teams who are doing very well. So it's going to be very tough until the end. They have to recover. And not only win the games at home but especially away games."