Northampton booked a money-spinning fourth-round FA Cup tie with Manchester United after coming from behind for a deserved win at Rotherham.
Paul Hurst put Rotherham ahead when he clipped a free-kick over the wall and in off the underside of the bar.
Town hit back when Richard Walker headed in Martin Smith free-kick.
And Smith clinched victory for the Cobblers with a free-kick from the left early in the second half to set up a mouth-watering tie against United.
The tone was set in the opening quarter-of-an-hour as the pace of Derek Asamoah wreaked havoc.
Twice the diminutive frontman shot wide after turning the home defence inside out and a Chris Carruthers cross from the left only just eluded his lunge after he found space at the far post.
Northampton were left with a mountain to climb after the Millers had taken the lead in the 19th minute.
Chris Carruthers’ handball on the edge of the area was spotted by the linesman – and Hurst stepped up to clip a precision free-kick over the wall and in off the underside of the bar.
Despite starting the contest 48 places below their hosts on the Football League ladder, it was the midlands team which created the better chances.
They almost drew level just six minutes after Hurst’s opener when Smith, who scored the equaliser at Sixfields, thudded a long-distance effort off the base of Mike Pollitt’s left-hand post.
Rotherham were consigned to hopeful high balls into the area which were repeatedly repelled by an organised Cobblers backline and visiting goalkeeper Lee Harper’s only save of note arrived in injury-time when he dived to his left to hold John Mullin’s glancing header.
Moments later, the 1,000-strong away supporters were left to savour the moment and revel in the prospect of meeting Sir Alex Ferguson’s champions.
Rotherham: Pollitt, Shaun Barker, Swailes, Minto, Hurst, Sedgwick (Monkhouse 76), Talbot, Mullin, Warne (Garner 63), Richard Barker (Butler 63), Byfield.
Subs Not Used: Montgomery, Daws.
Booked: Byfield, Hurst, Talbot.
Northampton: Harper, Reid, Sampson, Willmott, Lyttle, Carruthers, Trollope, Hargreaves, Smith, Asamoah (Richards 83), Walker. Subs Not Used: Thompson, Chambers, Lincoln, Harsley.
Booked: Sampson.
Attendance: 9,405.
Referee: R Oliver (W Midlands).