Champions League - Benitez: Ayew a danger for Arsenal
Marseille top Group F with two wins from their opening two games against Olympiacos and Borussia Dortmund, while Arsenal are in second having drawn in Germany and won at home to the Greek side.
The Gunners have endured a difficult start to the season and Wenger has found himself under real scrutiny with his team in tenth place after winning only three of their eight games in the Premier League this season.
While Marseille have fared even worse - Didier Deschamps leading the side to one win in 10 in Ligue 1 - Benitez expects them to be a difficult proposition, particularly with Ghana international Andre Ayew in attack.
"I have seen him before," Benitez told Eurosport of the forward. "This kind of player has the quality, the ability and he can change the game.
"Arsenal is not very physical ...this player will be very dangerous for them.
"Arsenal they have some problems. They play Song as a centre-back (in recent games), now Sagna is injured for a while, so they have to adapt so many things.
"I think it will be difficult for Arsenal ... Marseille at home will be dangerous for Arsenal."
However, Benitez is backing Wenger to turn things around at Emirates Stadium, even if a title challenge now looks to be beyond the North London club.
"It's the worst in terms of beginning (to the season), but he has qualities, experience, he knows the club, the team," Benitez said. "It's question of time.
"Arsenal is still a good team, with a great manager. The problem is when you have two or three other teams at the top of the table, not all of them will make mistakes.
"So now for Arsenal the goal is maybe to be in the top four ... so they cannot wait to react. They have to do it quickly."