DUNDEE UNITED stormed the Ibrox fortress and left title chasing Rangers in a Winters blunderland.
Robbie Winters scored one goal and made another for Kjell Olofsson to give Celtic a helping hand on a fright night for Walter Smith's men.
Victory would have lifted them eight points clear, but like Celtic 24 hours earlier at Kilmarnock, they were left red faced.
Instead Tommy McLean's Scottish Cup semi finalists stretched their unbeaten run to 15 games. And they became the first domestic opposition to beat Rangers at Ibrox in 24 matches.
So the gap at the top is five, points with Celtic, surely, taking inspiration for the Parkheadder by on Sunday.
There were howls of frustration and anger from the Rangers fans, but few could deny it was a tactical triumph for McLean.
In fact, Rangers had made a bright enough start. Sieb Dykstra was forced to claim a cross from Brian Laudrup and then they forced a corner.
In the 11th minute, Jorg Albertz burst through from midfield to fire in a low left foot shot which fizzed just wide of the target.
United's Norwegian marker Erik Pedersen, who successfully smothered Laudrup when Rangers were beaten at Tannadice in December, looked in the mood to perform a similar job on the influential Dane.
Rangers might have gone in front in the 15th minute when Alex Cleland blazed a cross from fellow - full back Craig Moore over the top - with Dykstra helpless.
Gordan Petric was booked and worse was to follow for Rangers as United snatched the lead with a lightning break out of defence.
Maurice Malpas released Kjell Oloffson and his pass was perfect for Winters to steer the ball beyond Andy Goram for his 11th goal of the season.
Gordon Durie missed a glorious chance to level in the 37th minute when Charlie Miller set him up but he fired over the bar.
Then Goram had to scramble to tip away a header from Winters - the pace of United's break again too hot for the Rangers defence of Alan McLaren, Petric and Joachim Bjorklund to handle.
Rangers replaced Petric with Trevor Steven at half time as they sacrificed a defender in search of an improvement.
But they were caught on the break again just 75 seconds after the re start as United streaked upfield from a Rangers corner to make it 2-0.
This time Winters supplied the pass and Olofsson nudged the ball beyond Goram with the Rangers defence left in his slipstream.
Winters had two more shooting chances before Smith sent on Ally McCoist after 63 minutes with Albertz withdrawn. The German looked less than pleased as he took off his shirt and strode down the tunnel.
Durie's 85th minute shot clipped an upright, but United's blanket defence deserved their clean sheet.