KR Reykjavík 0-1 Celtic FC
Ronny Deila's new side will take a slender lead into the second leg thanks to Callum McGregor's late goal on his Celtic debut.
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Callum McGregor marked his Celtic FC debut with a late goal as Ronny Deila's new team eventually breached an organised KR Reykjavík defence in the first leg of their UEFA Champions League second qualifying round tie.
In a game of few clear-cut chances, Celtic always looked the likelier scorers in Deila's first competitive fixture since succeeding Neil Lennon, hitting the woodwork three times. The breakthrough arrived with six minutes left when McGregor struck with a deflected shot from inside the penalty area.
Celtic first came close to scoring after nine minutes when Leigh Griffiths picked out Kris Commons, who hit a fantastic volley against the top of the crossbar.
Griffiths himself was denied by the frame of the goal on the hour and the Hoops were frustrated for a third time 18 minutes later when Teemu Pukki followed up another Commons shot. After he rounded KR goalkeeper Stefán Magnússon, Pukki could only fire off the outside of the post.
The winner came when McGregor cut in from the right before firing a low shot past Magnússon with the aid of a slight deflection. The second leg takes place at Edinburgh's Murrayfield next Tuesday.