Hamilton 3 Rangers 3:Scottish Cup holders Rangers were forced to battle for a 3-3 draw after almost being dumped out at the fourth round stage by Hamilton at New Douglas Park.
Walter Smith's men appeared to be cruising after goals from Steven Whittaker and Kenny Miller, before Simon Mensing pulled a goal back from the penalty spot.
Accies then stunned their visitors when Marco Paixao and Mickael Antoine-Curier both netted in injury time of the first half, with Rangers suffering the added blow of Steven Davis and Kris Boyd limping off injured.
However, Miller spared Rangers' blushes when he grabbed his second of the day from the penalty spot to ensure both teams have to do it all again.
The replay at Ibrox will be played on Tuesday January 19 while the winner has been drawn to play away at St Mirren in the fifth round.
After the game Mensing was among the players questioning whether referee Charles Richmond cost them a famous victory by penalising Stuart Elliott for handball inside the box while laying on the floor.
Mensing said: "Stu is down on the floor and whether he's stuck his arm out I don't know, these things happen and you have to get on with it."
Former Rangers midfielder Neil McCann, in his role as a Sky Sports pundit, said: "How on earth is he meant to get his hands out of the road?"
Miller added: "It was a bit harsh that his hand was on the floor but there was no doubt it hit his hand."
Hamilton boss Billy Reid added on Sky Sports: "It was a fantastic comeback in the first half. We got a break with out penalty then we were absolutely brilliant.
"We could have done better in the second half."