In a game that was affected heavily by the weather, Chesterfield produced a spirited performance to come from a goal down to beat the Cobblers.
Darren Carter smashed home a penalty early in the game but Chesterfield fought back with goals from Dan Gardner, Gary Roberts and Armand Gnanduillet to secure a vital away victory to keep their promotion hunt on track.
Chesterfield started the better of the two sides, forcing a succession of early corners but unfortunately they failed to find the head of an attacker.
For all the Spireites dominance, Northampton were awarded a penalty in the 15th minute as Tommy Lee brought down Hallam Hope. Carter stepped up and sent the goalkeeper the wrong way to give the home side the lead.
The goal seemed to lift the home support but it was the Spireites again that looked the most threatening. Dan Gardner, who was making his first Chesterfield start, went close on 20 minutes but his effort just dragged wide.
It didn’t take long for the forward to equalise for the Spireites a couple of minutes afterwards. After a quick free-kick, Gardner received the ball and smashed it past the goalkeeper on the angle to score his second goal in a Chesterfield shirt.
The conditions were really starting to affect the play as a mixture of heavy rain, hail and thunder & lightning were proving difficult to deal with for both sides.
With the pitch deteriorating, the Spireites kept focused and were trying to force a goal. Eoin Doyle almost found a way through after Ollie Banks played him through but captain Lee Collins cut out the danger.
During the half time break, the rain seemed to calm down and the referee deemed the second half playable.
It was the home side that had the first opportunity of the half as Gary Deegan drove an effort along the slippery surface, but Lee was right behind the ball to save comfortably.
The sun started to shine, rainbows appeared and the day got a lot better for the Spireites as Roberts put them ahead. A mistake from former loanee James Hurst allowed Doyle to play it through to the winger, but as the ball held up in the water, his first shot was blocked. At the second attempt Roberts lifted the ball over Matt Duke and expertly finished from the edge of the box.
Soon after the goal, Gardner became the first player to go into the referee’s notebook after holding Joe Widdowson back illegally.
Chesterfield were in the ascendency and almost caught the Northampton defence out on several occasions, but Duke cleared up at the back for the Cobblers.
Banks left the field on the hour mark and was replaced by Armand Gnanduillet. The Frenchman made a strong impact on the game, winning headers and causing a nuisance in attack.
Chesterfield made their second substitution of the game on 70 minutes as goalscorer Gardner was replaced by Jay O’Shea.
With just over ten minutes remaining, the Cobblers almost snatched a leveller. After a long goalmouth scramble, the ball for to Matty Blair who looked to strike the ball home but Ritchie Humphreys leaped from nowhere to clear the danger for Chesterfield.
Sam Hird was introduced as the Spireites final substitution replacing Doyle and Chesterfield returned to a 4-5-1 formation.
With Northampton piling on the pressure going into the final couple of minutes, Ian Evatt powered a header towards Gnanduillet and he comfortably slotted his shot past Duke to put Chesterfield out of site.
The final whistle sounded to the delight of the 933 visiting supporters and they head back up the M1 the happier of the two sides.
Northampton Town: Duke; Hurst (Morris 64'), McGinty, Collins (c), Widdowson; Tozer, Carter (O'Donovan 66'), Deegan (Hooper 75'), Blair; Hope, German.
Subs not used: Demontagnac, Snedeker, Harriott, Kouo-Doumbe.
Chesterfield: Lee; Darikwa, Evatt (c), Cooper, Humphreys; Ryan, Morsy, Gardner (O'Shea 75'), Banks (Gnanduillet 63'), Roberts; Doyle (Hird 83').
Subs not used: Dunbavin, Brown, Smith, Togwel.