Arsenal slipped up in their bid to top their Champions League group as they went down 2-0 at FC Porto while the Guynners' premiership rivals Manchester United fared better, drawing 2-2 at home to the Danish side Aalborg,
The Scottish champions Celtic ensured United topped the group by beating 10-man Villarreal 2-0 in Glasgow for their first win of the campaign.
Arsenal's loss means they avoid having to play Real Madrid, who beat the UEFA Cup holders Zenit St Petersburg 3-0.
Juventus topped the group though after drawing 0-0 at home to the Belarus side BATE Borisov.
Bayern Munich topped the other group with 3-2 win over Olympique Lyon.
Zenit will still get a chance to defend the UEFA Cup and are joined by fellow third-placed sides Aalborg, Fiorentina and Dynamo Kiev.
