A-League champions Brisbane Roar's Asian Champions League qualifier against Thailand's Buriram United has gone into extra-time after a goalless 90 minutes at Thunder Castle Stadium.Goalkeeper Michael Theo has been the hero for the Roar in regulation time, pulling off a string of clutch saves - particularly in the first half when the energetic home side relentlessly pressured Brisbane.The Roar worked their way into the match in the second half and had the better of the late chances as Luke Brattan, Stef Nijland and Ben Halloran impressed.If the sides can't be separated after 30 minutes of extra-time then the match, and a spot in Group E, will be decided by penalties.