The Cobblers made it four wins on the bounce with an excellent victory at Accrington which was secured despite the sending-off of Ryan Cresswell.
The 5-1 victory is Northampton’s biggest away win since the 4-0 win at Macclesfield in March 2004 and takes them to the top half of the Sky Bet League Two table and within seven points of the play-offs.
Marc Richards scored twice - once from the penalty spot - to take his personally tally for the season to 15.
Ricky Holmes had earlier opened the scoring and Lawson D’Ath notched twice on a truly memorable afternoon for the 317 away supporters in attendance.
Their team started positively and were in no trouble until Cresswell’s red card, at which point they played a counter-attacking game which was equally effective and brutally ruthless.
Northampton named the same starting 11 for the fifth game and made another brisk start, with Marc Richards unsettling goalkeeper Matt Macey as he claimed a long ball over the top but John-Joe O’Toole was unable to reach the loose ball.
Within just five minutes, they had the lead, Holmes bursting outside his full-back and firing home an unstoppable shot via the underside of the crossbar.
Several visiting players were furious with referee David Webb and what they felt was his failure to spot an elbow on Richards before a five-minute spell in which the tackles really started to fly.
Former Accrington player Joel Byrom was on the wrong end of a stern challenge from Andrew Procter, an old friend of his, but recovered to unleash an exocet of a shot just over the bar.
Goalmouth action was in short supply until the second goal, which came from the spot after Holmes was tripped in full flight by Adam Buxton.
Macey got to the shot but it squirmed under his body and Richards turned away to celebrate another goal in an excellent season for the striker.
Accrington got back into the game in the 39th minute, when Sean Maguire raced onto a pass over the top and was fouled in the box by Cresswell.
Cresswell was sent off and, although Matt Duke saved Luke Joyce’s penalty, Piero Mingoia reacted quickly to despatch the rebound with the goalkeeper still on the floor.
The home side freshened up their forward line with a double half-time substitution but it was Northampton who made the brighter start, Holmes failing to connect with Evan Horwood’s excellent ball in behind the defence.
Mingoia hit a shot from distance which required a good low save from Duke after it deflected and Adam Buxton drove a long-range effort narrowly wide.
Their domination, however, did not lead to a goal and they were made to pay when a counter-attack saw Jason Taylor play in D’Ath - who looked well offside - to steer a lob over Macey.
Things went from bad to worse for Macey, who did not come out to collect a ball Rob Atkinson was shepherding back to him, D’Ath robbed him and played a square pass to Richards to drill into the roof of the net from 15 yards.
There was still time for more. Holmes played an excellent pass from deep on the left wing for D’Ath to collect, advance on Macey and coolly slot into the bottom corner.
Accrington: Macey; Winnard, Connelly, Atkinson, Buxton; Procter, Joyce; Naismith, Maguire, Mingoia; Carver
Subs: Gray (for Carver 46), Barry (for Procter 46), Windass (for Naismith 68)
Not used: Dawber, Liddle, McCartan, Hunt
Cobblers: Duke; Moloney, Cresswell, Collins, Horwood; Byrom, Taylor; D’Ath, O’Toole, Holmes; Richards
Subs: Diamond (for O’Toole 39), Bodin (for Holmes 83), Hackett (for D’Ath 83)
Not used: Snedker, Carter, Tozer, Toney
Away fans: 317