Arsenal captain Thomas Vermaelen has identified diminutive French forward Mathieu Valbuena as a dangerman as Arsenal take on Marseille tonight.
The France international has played every one of his team's Group F fixtures and has contributed four assists in Ligue 1 this season. Vermaelen believes the Gunners must keep Valbuena quiet if they are to get all three points.
Read the captain's notes in the official matchday programme
"Tonight's game is a must-win, because the group is as strong and close as we all thought it would be when the draw was made," the captain told the matchday programme.
"Marseille are the only team in the group who can't go through, but I heard they did very well in their last game against Napoli, and were ahead in that match, so we expect them to give everything tonight too.
"We have already beaten them once this season, but that was a tough match too.
"They have some very good individual players in their side, players like Valbuena especially can be very dangerous. He's their main playmaker, just behind the strikers, so we'll have to watch him carefully and not give him any space to cause us problems, and from then on we want to take control of the match ourselves."