We scored twice in second-half stoppage time to secure a remarkable 3-2 victory over Chesterfield in the Vanarama National League.
Enzio Boldewijn had given us the lead with his second goal of the season but the hosts levelled through Jonathan Smith before Tom Denton's second-half header looked to have won it going into three minutes of stoppage time.
But nodded efforts from Ruben Rodrigues and Kyle Wootton ensured there was even more injury-time drama than in midweek, when Halifax scored at the death to earn a point, as we went on to win the game.
Neal Ardley made two changes to the side that played at the Shay, where Alex Lacey was forced off at half-time with a heel problem which would also keep him out of our trip to Chesterfield. Ben Turner, his replacement on Tuesday, took his place in the starting XI.
The other switch came in attack, with Tuesday's goalscorer Elisha Sam dropping to the bench in place of Cal Roberts.
And, shortly after Boldewijn and Smith had fired off-target at either end, Roberts nearly opened the scoring when he cut in from the left and crashed a 20-yard shot off the post.
The Geordie was in the thick of the action again three minutes later, wriggling his way along the touchline before seeing his shot saved by Corey Addai at his near post. The resultant corner was initially cleared before Richard Brindley looped the ball towards the back post for Turner to head goalwards, only for Addai to parry the ball away.
There was a sense of deja vu moments later when Turner rose highest to get his head to O'Brien's corner. Addai was once again able to make the save but this time Boldewijn was on hand to turn the ball home from close range.
Roberts had a glimpse of making it 2-0 shortly after the restart when the ball bounced for him with Addai in no man's land. The winger couldn't guide his lobbed, longe-range effort goalwards.
We weren't having it all our own way, though, and Sam Slocombe had to make a strong 26th-minute save to keep Curtis Weston's volley out.
And, with 12 minutes to play in the half, the hosts rounded off a neat move with an equaliser from Smith, who sent the ball low across Slocombe and into the far corner from just outside the area.
Dion Kelly-Evans went into the book for a foul on Jordan Cropper and then Cropper followed suit when he felled Boldewijn in a dangerous position in stoppage time. Roberts couldn't find a way past the wall, though, and we headed into the break level.
There were no changes at half-time and, after a quiet start to the second period, Ardley sent Rodrigues and Sam on for O'Brien and Boldewijn.
Moments before, Boldewijn had linked up well with Roberts to release him into the area, only for Addai to save his shot.
And Chesterfield had a good chance of their own on 65 minutes when Tom Denton controlled a loose ball on the edge of our box and, instead of taking the chance on himself, squared the ball to his namesake Tyler who could only fire it over from the edge of the area.
But, after Sam had fired a speculative effort over and Weston had seen a long-range effort saved, Tom Denton did get his name on the scoresheet with 12 minutes to play when he stooped low to head home a cross from the left.
Kyle Wootton had a glimpse of goal on 84 minutes when Michael Doyle picked him out with a low cross but, under pressure, the forward couldn't make meaningful contact with an attempted first-time shot.
As we entered added time it looked like we'd be heading back down the M1 with nothing to show for our afternoon's work but, within moments of the fourth official showing his board, Rodrigues had got his head to a loose ball in the Chesterfield box to haul us level and set up the most dramatic of finales.
The winner came from yet another header, this time Wootton nodding home a cross from the right - the ball just squeezing underneath Addai as euphoric scenes ensued.
NOTTS XI: Slocombe; Kelly-Evans, Turner, Rawlinson, Brindley; Doyle, Reeves, O'Brien; Boldewijn, Roberts, Wootton
SUBS: Graham, Chicksen, Rodrigues, Knowles, Sam