Six minutes from the final whistle Eidur Sigurbjonsson scored the only goal of the game to give the Icelandic champions a lead to take to Norway.
Celtic will be at home in the first leg which will be played on July 24 or 25 before the trip north for the return leg- assuming they avoid a four goal home defeat from Alashkert!
Last season Brendan Rodgers’ side were drawn against Rosenborg at the same stage and went into the home leg without any strikers.
A hamstring injury ruled Moussa Dembele out of the qualifying campaign while Leigh Griffiths had picked up a suspension for celebrating Celtic’s win away to Linfield.
Celtic struggled to a 0-0 draw at home but shortly after Griffiths came off the bench in the return leg James Forrest scored the goal that took Celtic through to a play-off against Astana.