GLASGOW - Kilmarnock ended a 57-year wait for a win at Celtic Park as goals in either half condemned the leaders of Scottish soccer's Premier League to a 2-0 defeat.
Celtic, who suffered an agonising last-gasp defeat to Barcelona midweek, showed all the signs of suffering a European hangover as they made a sluggish start.
Joe Ledley somehow missed from close range for Celtic before Cillian Sheridan seized on some slack defending to race in on goal and calmly round Fraser Forster to net against his old club in the 43rd minute.
Forster kept the Hoops in the match with a superb stop from James Dayton but could do nothing to stop Liam Kelly's fiercely-driven 62nd-minute penalty after Emilio Izaguirre had clipped Rory McKeown in the box.