Chelsea too strong - Petit
League leaders Chelsea will welcome London rivals Arsenal to Stamford Bridge, with six points separating the two teams.
Chelsea have been rampant this season, with new recruits Diego Costa and Cesc Fabregas leading the charge for Jose Mourinho's men, who have dropped just two points in six games.
Arsenal are also unbeaten, though they have been less convincing in their two wins and four draws thus far.
While Arsenal look almost flawless in possession at times, defence remains an area of concern for Arsene Wenger and Petit - a former Arsenal and Chelsea player - feels that could be the club's downfall against a physically superior Chelsea.
"Arsenal have players who are great on the ball, don't get me wrong," Petit told the Mirror.
"But when they lose possession, they seem to have a problem. When they can control a game, great.
"But they do not seem to score many from set-pieces while Chelsea are always a threat from that kind of situation.
"At times, it seems like Arsenal have forgotten how to defend. They are missing some power in their team."
Petit added: "I think Chelsea have a great balance to their squad and they have a bigger physical presence. You look in midfield and Chelsea have Cesc Fabregas and Nemanja Matic.
"You look at the central defence, with John Terry and Gary Cahill. Arsenal are great when they can play their normal game, on the grass, passing along the ground.
"But if they lose the ball, they are not well equipped to win it back. I believe that is where Chelsea have an advantage.
"And they also have Diego Costa. He has become the player they missed when Didier Drogba left. They have found the man to replace him. He has been tremendous with his goals.
"You can play the ball long to him or short. And that strong midfield of Fabregas and Matic enables players like Eden Hazard to have the time and the space to link up with Costa."