Sanogo has seen a number of players climb above him in the pecking order at the Emirates Stadium after struggling to produce his best form in the early stages of his Gunners career, and Diaby believes that he can help his fellow Frenchman achieve success.
"It's [about being] somebody who is going to advise you all the time and who is going to tell you the truth when you do something bad. For a young player it's really important that somebody on the side has their eyes on your objective," the midfielder told members of the media.
"Yaya sees me as an older brother so it is my duty to help him be comfortable in the squad and at the club. It makes things easier for him and I could see that he needed help, so we need to be there to help him succeed at the club.
"We get along well because we both started at Auxerre and we have had similar injuries. When he talks to me I understand what he's saying because I've been through all of it - the struggle that he went through."
Sanogo has not featured in the Arsenal team yet this season.