Second Division leaders Morton knocked top-flight Kilmarnock out of the Tennent's Scottish Cup with a stunning 3-1 win.
The SPL club seemed to have weathered an early storm and took the lead just after the break through Colin Nish.
But the home side hit back with a Chris Templeman double and another striker from Paul McGowen.
Kilmarnock made three changes for the match as Steven Naismith, Allan Johnston and Colin Nish returned to the starting line-up after suffering from a virus.
Rhian Dodds, Peter Leven and Stevie Murray were dropped to the bench after starting in Tuesday's 2-0 defeat at Celtic in the SPL.
Scottish League Division Two leaders Morton named an unchanged team, with new signing Bobby Linn ineligible after playing for Peterhead in an earlier round.
After a 10-minute delay to the kick-off, to let queueing supporters into the stadium, the hosts wasted no time in trying their luck when Dean Keenan's 25-yard strike zipped inches over.
Danny Invincibile had two half chances for Killie, slicing the first and being crowded out soon after.
But it was Morton who were doing most of the pressing.
Paul McGowan had a penalty claim rejected by Mike McCurry after getting in front of Simon Ford and going down rather too easily.
Moments later Chris Templeman's 25-yard effort was pushed wide by scrambling Killie goalkeeper Graeme Smith.
A great move from the hosts ended in an offside flag against Templeman and on-loan Celtic striker McGowan saw his chip just clear the bar.
Morton goalkeeper Paul Mathers was eventually called into action midway through the half and was grateful to see the ball cleared off the line after he had partially blocked Naismith's shot.
Mathers then pushed away Naismith's volley after a high ball had fallen for the winger.
Johnston burst towards the edge of the box but could not get enough power in his left-footed strike to trouble the veteran keeper.
The game was moving from end to end and Templeman just failed to turn his header on target from Jim McAlistair's deep cross.
The former Brechin forward then headed two yards wide from Jamie Stevenson's dangerous free-kick. His threat, even at that stage, was obvious.
Yet Kilmarnock went in front when Colin Nish scored from close range in the 47th minute.
They looked to have gained control, but the match turned dramatically when Templeman struck twice in quick succession.
His first came from 20 yards in the 62nd minute, and six minutes later he put Morton in front from closer to goal.
Four minutes later the hosts scored again when McGowen poked the ball home after a superb break down the left by McAlistair.
The visitors struggled to create any chances and Morton could have made it worse as Templeman had two decent penalty claims rejected.
Frazer Wright had a header saved in injury time as Killie limped out of the cup.