Michael Cox on the Ligue 1 side's three biggest threats to the Gunners' cause...
Arsenal's sensational deadline-day signing of Mesut Ozil provides Arsene Wenger with one of Europe's most talented No.10s - but tonight the Gunners' German new boy may be up against a playmaker of similar quality.
Mathieu Valbuena hasn't yet lit up international football or the Champions League, but his performances over the past couple of seasons for Marseille have been exceptional – last season he created more chances than any other player in Europe's major five leagues.
Marseille are a naturally cautious, structured and rather boxy side that keep it tight in central positions and attack primarily down the flanks. The interesting thing about their play is the relationship between Valbuena and centre-forward Andre-Pierre Gignac. Rarely receiving positive forward passes from the midfield zone, they instead have to drift into wider positions to collect the ball.
They do this in a clever manner, laterally moving across the pitch into wider zones, but always remaining close to one another. Gignac, for example, appears a straightforward No.9 on first glimpse, but is actually more intelligent and varied with his movement than you might expect, working the channels and drawing opposition centre-backs out of position.
Valbuena, however, is the true star of the side. His quality comes from his positional variation - he has the ability to move in all four directions, drifting wide to cause overloads on the flanks and crossing the ball, pushing forward to create a proper front two with Gignac, or dropping deeper to become a third central midfielder and ensure Marseille dominate the centre ground.
His display against PSG last season was sensational, even in a 2-0 defeat. Valbuena managed to play the most passes on the pitch, had the best pass completion rate and created the most chances.
His relationship with Gignac was also obvious throughout – they combined 21 times in a variety of positions, and created four chances for one another.
Arsenal will have to be particularly careful of Marseille's ability to attack in the channels. This has been a consistent problem for the Gunners this season - Laurent Koscielny has been drawn out of position and into some rash tackles, while Bacary Sagna was caught out against Jozy Altidore at the weekend.
Arsenal will know all about Andre Ayew having played Marseille last season, but newcomer Dimitri Payet is also a threat from wide – he starts from the right but moves inside into dangerous central positions. He’s also a goal threat, scoring twice on his Marseille debut earlier this season.