Goals from Cillian Sheridan and Liam Kelly gave Kilmarnock a 2-0 victory over Celtic - their first win at Parkhead for an incredible 57 years.
Former Celt Sheridan set the visitors on the way to their historic victory two minutes before the break when he capitalised on slack play by Efe Ambrose to race clear and round keeper Fraser Forster before scoring into an empty goal.
Midfielder Kelly slammed in the second from the spot just after the hour mark when Hoops left-back Emilio Izaguirre was adjudged to have fouled Rory McKenzie and the spirited Rugby Park men held on for their first success in the east end of Glasgow since 1955.
Neil Lennon's men had put in a disciplined, battling performance against Barcelona in the Nou Camp in midweek, only to lose the Champions League clash 2-1 in the final seconds of injury-time.
The first real moment of excitement came in the 16th minute when Rugby Park defender Rory McKeown did well to head an Izaguirre cross away for a corner under pressure from Miku but the set-piece came to nothing. In the 26th minute Joe Ledley missed a sitter by stabbing awkwardly at the ball and watching it fly past the post.
The Hoops fans grew increasingly disgruntled and they let their feelings be known when Sheridan gave Killie the lead. Ambrose, who had swapped places with Charlie Mulgrew in central defence, was too casual after taking a pass from Adam Matthews and the Irishman got the break of the ball which left him in a race with Forster.
The Hoops keeper came, then stopped, allowing Sheridan to take possession and he was coolness personified as he rounded Forster to walk the ball towards the empty goal before knocking it in.
Gary Hooper should have levelled in the 53rd minute when James Forrest set him up with a cross at the near post but he missed the target. Forster came to Celtic's rescue moments later, tipping over the bar after James Dayton had run through the middle of the parting Parkhead defence before thundering in a drive from outside the box.
The tension was building and Killie's penalty came in the 61st minute when McKenzie had his heel clipped by Izaguirre just inside the box as he set himself to have a shot after driving at the nervous Hoops defence. Forster was booked by referee Crawford Allan for delaying the spot-kick but that did not affect Kelly who hammered his shot past the big Geordie.
In the 76th minute Izaguirre had the ball in the Killie net after taking a Paddy McCourt pass but was ruled offside. With four minutes remaining Cammy Bell parried Tony Watt's angled-shot from 16 yards but by that time much of the belief had been sapped from the Hoops players and certainly their fans, allowing the small band of Killie supporters their moment of glory at the end.