Minutes before the draw in Nyon, Polish club Legia Warsaw, who had handed Celtic a 6-1 third qualifying round defear to, were ruled out. Legia were demoted to the UEFA Europa League play-offs for fielding an ineligible player.
Arsenal, meanwhile, must over overcome Besiktas to seal their 17th consecutive appearance in the Champions League group stages. Last season the Gunners saw off another Turkish club, Fenerbahce, to go on to make it into the Last 16 where Arsene Wenger's side, finalists in 2006, came a cropper against Bayern Munich.
The first leg ties are scheduled for August 19/20, with the second leg matches on August 26/27. The ten winners will join the 22 teams automatically qualified for the group stage, which gets underway in September.