Cobblers suffered injury-time heartbreak when they crashed out of the FA Cup at the first time of asking after Bruno Andrade's late winner sent Lincoln City through to round two with a breathless 3-2 victory at Sincil Bank on Saturday.
Town's four-game winning run was brought to a halt in a cracking game which saw the visitors recover from a two-goal deficit to draw level at 2-2 late in the second-half, only for Andrade's exquisite finish to snatch it for the table-topping Imps.
Harry Anderson's well-worked first-half goal had the home side ahead at the break and they looked to be making serene progress when Tom Pett found the bottom corner just short of the hour-mark, but Cobblers displayed tremendous spirit, Jack Bridge and then Kevin van Veen both scoring to set up a high-octane finish.
It was not to be, however, with Andrade curling into the far corner in stoppage-time to send Northampton out of the competition at the first hurdle for the second year in a row, handing Keith Curle only his second defeat in charge of the club.
To compound his and Town's fans' misery, Junior Morias was shown a straight red card for an unnecessary incident in the dying embers and will now face a three-game ban.
Morias was only returning from a long-term injury to take his place on the bench at Sincil Bank and Jack Bridge replaced Matt Crooks in the only change to the team which beat Crewe in the league last weekend.
League Two leaders Lincoln have stuttered a little of late but they were sharper out of the traps on on Saturday with John Akinde's ominous start suggesting Aaron Pierre and Jordan Turnbull were in for a busy afternoon.
He almost latched onto a through pass and then shot wide from 20 yards, but it was another player who put Northampton behind after 18 minutes. Slick interplay between Harry Toffolo and Bruno Andrade down City's left was followed by an enticing low cross that the on-rushing Anderson blasted first-time beyond David Cornell.
Hakeem Oddofin blocked from Jason Shackell and Cornell kept out Shay McCarton as the Imps, superior for much of the first-half, came dangerously close to adding a second goal.
McCarton's movement was causing a few issues for the visiting defence and he curled another shot just wide before Josh Vickers had his first piece of goalkeeping to do, diving away to his right to claw John-Joe O'Toole's left-footed volley around the post.
But Lincoln's half-time lead was well-deserved and they resumed on the front foot in the second-half with McCartan, again the danger man, having a strong penalty shout turned out before he then fired into the side-netting.
The home side were two to the good 10 minutes after the break through their second fine finish of the afternoon, this time applied by Pett whose crisp shot from 20 yards nestled into the bottom corner of Cornell's net.
But no sooner had Lincoln doubled their advantage than they were pegged back. Within two minutes, a long throw founds its away to Bridge on the edge of the box and his low effort beat Vickers' unconvincing attempt and wriggled into the net for his first Cobblers goal.
Sensing an opportunity, Curle then threw on Morias for his first appearance since September 1, and the Cobblers were desperately close to levelling things up when Hakeem Oddofin bent a shot just the wrong side of the woodwork.
Van Veen sent a superb long-range attempt hurtling towards the top corner midway through the half but Vickers was at full stretch to beat it away, while opposite number Cornell thwarted both Anderson and the outstanding McCartan at the other end.
Just as time looked to be slipping away from the Cobblers, they were back on level terms with nine minutes remaining. Odoffin and Hoskins were the architects, working the ball well on the right side for the latter to cross for van Veen, who was given space and time to turn and shoot past Vickers.
That should have sent the tie to a replay but, with neither team wanting to add another game to their schedules, it was a frantic finish and Lincoln grabbed a dramatic winner in the first of five added minutes, Andrade brilliantly picking out the top corner with a curling effort from 25 yards.
It got worse for the Cobblers in the closing moments when Morias needlessly saw red for pushing over a Lincoln player, and that was swiftly followed by the full-time whistle.
Lincoln: Vickers, O'Connor, Shackell, Pett, Andrade (Wharton 90), Toffolo, Wilson, Bostwick, McCartan (Green 86), Anderson, Akinde (Rhead 78)
Subs not used: Slocombe, Chapman, Crookes, Mensah
Cobblers: Cornell, Odoffin, Turnbull, Pierre, Buchanan (c), Hoskins, O'Toole, McWilliams, Bridge (Powell 72), van Veen, Williams (Morias 60)
Subs not used: Ward, C McWilliams, J Williams, Roberts, Waters
Referee: Graham Salisbury
Cobblers fans: 568