Andy Williams struck in the fifth minute of injury-time to hand the Cobblers a dramatic first home win of the season and simultaneously end Forest Green Rovers’ unbeaten start to the campaign on an afternoon full of drama and excitement at the PTS Academy Stadium.
Williams’ last-gasp goal sparked wild scenes among fans, players and coaches as the roof almost came of the ground with Town coming from behind to win a game for the second time in a week, making it four unbeaten for Keith Curle.
Earlier, Aaron Pierre’s second goal in four days cancelled out Reuben Reid’s first-half opener but it was all about the heroics of Williams, who couldn’t have chosen a more opportune time to score his first goal for the club.
Few could have begrudged Rovers their half-time advantage, even if Reid’s goal looked suspiciously offside, after they delivered something of a footballing lesson for the first 45 minutes in difficult, blustery conditions.
But Northampton used the elements to their advantage in the second-half as Pierre’s header levelled proceedings and Williams won it at the death, temporarily lifting the Cobblers to 19th in Sky Bet League Two, and allowing everyone to breathe a big sigh of relief.
Curle reverted to the same side that drew with Swindon Town last weekend but for one alteration as Billy Waters replaced Shaun McWilliams at right wing-back.
Matt Crooks was off target with an early header but the more confident start came from the unbeaten visitors and home goalkeeper David Cornell had to be on his guard throughout the first-half.
Town’s defence backed off to allow Dayle Grubb to take aim towards the far corner but Cornell was at full length tip away before Reid’s fierce hit was straight into the goalkeeper’s midriff.
In-form Rovers were quickly into their stride but Town weren’t without their own moments of danger and Robert Sanchez reacted smartly to keep hold of Waters’ low shot from inside the penalty box.
But the better, more purposeful play was produced by the away side who knocked the ball around with impressive confidence and fluency with Lloyd James the next man to force Cornell to tip wide of his near post.
The Cobblers were reduced to counter-attacks and the odd set-piece but it was from a quickly-taken free-kick that presented a good shooting opportunity for Waters, however he lacked the composure and snatched at the shot.
Liam Shephard escaped the home defence and his lob landed on the roof of the net and then Grubb’s next attempt curled a whisker over the crossbar before Rovers took a deserved lead into the break.
The goal came with a huge dollop of controversy though as Reid appeared comfortably offside when he latched onto Reece Brown’s long ball but no flag was forthcoming, much to the home side’s disbelief, and Reid did the rest, rounding Cornell and rolling into the net.
Northampton at least had the benefit of the wind in the second-half although they showed little sign of utilising it until Sam Foley almost caught Sanchez off guard from range.
That gave the home side impetus and, just past the hour-mark, they were back level.
David Buchanan delivered a deep corner to the far post where Jordan Turnbull headed the ball back intot the danger area, and Pierre was on hand to bullet a header into the bottom corner.
It was now an entirely different game as Town, aided by the conditions, penned Rovers back into their own third and carved out two or three half chances without seriously testing Sanchez.
A free-kick awarded for handball gave Sam Hoskins the chance to go from goal 20 yards out but Sanchez was equal to his low effort before Rovers just about hacked away from the following goalmouth scramble.
The visitors came more into it in the final 10 minutes but Hoskins had another chance to snatch all three points in the second of six added minutes, his scuffed effort agonisingly rolling the wrong side of the woodwork.
That looked to be the last chance of the game but Kevin van Veen had other ideas as he did superbly to win the ball back and tee up Williams, who made no mistake in beating Sanchez as the home fans went wild and all three points were dramatically secured.
Cobblers: Cornell, Facey, Turnbull, Pierre, Waters (Powell 90), Foley, O’Toole, Crooks (van Veen 57), Buchanan (c) (Bridge 79), Hoskins, Williams
Subs not used: Ward, Odoffin, McWilliams, Bowditch
Forest Green: Sanchez, Shephard, James (Pearce 78), Rawson, Winchester, Grubb, Brown (Williams 66), McGinley, Digby (c), Mills, Reid (Gunning 66)
Subs not used: Collins, Montgomery, Archibald, Worthington
Referee: Ollie Yates
Rovers fans: 234