The Gunners' away woes continued on Sunday afternoon as they let a one-goal lead slip to lose 2-1 against Newcastle United at St James' Park.
Arsenal had six players in their own half to cover three opposition men in the build-up to Matt Ritchie's winning strike, leaving former Manchester United skipper Vidic with little doubt as to where the Londoners need to improve ahead of next season.
"I think there is a lack of communication, they are watching the ball and not reacting," he told Sky Sports News. "There are six players against three and there is no communication about who is going to go and attack the ball, who is going to cover. It seems like in this situation, it is definitely organisation, and I can't say a lack of desire because I saw them in the first 20 minutes and they were really attacking and aggressive.
"I think communication is the key. Everyone is watching what the other player is going to do, no one is saying 'you attack, I'll go behind'. I did that my whole career with Rio [Ferdinand], Patrice [Evra] and players I played with, we always had a communication between us. It's wasn't just us waiting to see what was going to happen, we communicated all the time throughout the game.
"They have to defend. For me, when Arsenal get to pre-season, they don't have to think about scoring goals, they need to think about keeping a clean sheet because that is what they have to learn - to defend.
"That's the key if they want to challenge for the title because I think in the end, they will score 70 goals a season but they will concede 40. For a team who is in the top seven who concede that many goals, I think they are doing well to be in that position."
Arsenal, beaten in all five away games since the turn of the year, are just two points better off than seventh-placed Burnley.