Arsenal midfielder Santi Cazorla has warned against complacency ahead of Tuesday's crucial Champions League encounter with Marseille.

The Gunners are top of Group F on nine points from four games, although Napoli are second only on goal difference.

Borussia Dortmund can draw level with Rafael Benitez's side on nine points if they win at the Westfalenstadion, meaning that any two of the three sides are still capable of reaching the knockout stages.

Meanwhile, Elie Baup's team have not taken a single point from any of their four games so far, but Cazorla has said that the French outfit still pose a threat.

"The main problem I see is everyone thinks it's going to be an easy game for us to win," the Spaniard told the club's official website. "There is nothing at stake for Marseille because they have zero points but they are going to make things difficult for us.

"It may be tough and if we're not careful we might slip up and then we might not be able to get through to the next round.

"We need to understand it's a vital match. If we obtained a bad result then it would make things very complicated for us to go to Napoli [on December 11] and win there."

The North Londoners take on Napoli at the Stadio San Paolo in their final group match on December 11.