4. Mathieu Valbuena
In his 7 years with the French club, Mathieu Valbuena has established himself as a household name at the Stade Velodrome. Renowned for his nibble footwork and defence splitting passes, the diminutive playmaker is a genuine match winner and a player Wenger must be wary of. Valbuena has progressed massively over the last two seasons, racking up 30 assists something which has not gone unnoticed by Europe's top clubs. At 28 the Frenchman is one of the leaders in an improving Marseille side and, while numerous managers have come and gone, Valbuena's has remained a key component of Marseille. It will be up to Arsenal's two holding players to cope with the French international. Specifically Mathieu Flamini, who will be returning to where his career began, will be expected to contend with the midfield playmaker. The Gunners simply cannot afford to give Valbuena time, as he will get his head up and pick them up off with his deadly accurate passing. However, Wenger's men must beware, get too tight and Valbuena is more than capable of rolling his opponent and driving towards the goal. Keeping Valbuena quiet will be a testing balancing act for Arsenal, but it is one they must get right if they are to succeed in Marseille.