Revenge was administered at Sixfields last night with as sweet a strike as this ground is likely to see all season.
Liam Davis struck a top-class volley to put Town in front against Leeds only to see that goal wiped out by a Jermaine Beckford header in the second half.
But late in the game on-loan striker Nicholas Bignall powered home a header to exorcise last Monday's FA Cup thrashing and give manager Stuart Gray his first win over the Whites at the fifth time of asking.
The home side's performance level improved immeasurably from the Cup game – take all the adjectives from that night, find their antonyms, and there's your description of events here.
Eyebrows were raised all around the ground when Gray's team selection was revealed – Liam Dolman and Mark Hughes both benched despite helping Town to a clean sheet in the win over Hereford on Saturday – but the call was spot on.
Andy Todd came in for his debut, and there was also a start in central midfield for Giles Coke.
The centre-half wasn't brought to the club for his crossing ability but sent over a peach of a ball for Scott McGleish in the fifth minute which the old favourite headed wide of the target.
The number five showed his muscle moments later with a clattering challenge on Beckford as the not-so-subtle quietening plan began to emerge.
Ryan Gilligan had already shown some nice touches when he decided to let fly from 20 yards on the 10-minute mark, the shot rattling the angle of bar and post.
This was one of Gilligan's best games for the club, and he will be delighted with how he performed.
McGleish then threaded a pass through for Constantine to race onto, but the shot was not a clean one and David Lucas gathered it with ease in the Leeds goal.
Constantine was enjoying a good game, and some neat skill on 27 minutes saw him deliver to the back post after beating his man.
Sadly for the Cobbers all their runners had gone to the front post and the cross was harmless.
The same could not be said of Davis' shot moments later.
Both the winger and his marker slipped as the ball came across but Davis reacted first to spring up and swivel a right-footed volley which Lucas had no chance of saving.
At the other end, Frank Fielding had nothing to do until the 32nd minute when a dangerous-looking Beckford shot required a flying block to keep it out of the net the rapid striker put two goals in a week ago.
Fielding blocked two more quickfire Beckford shots soon after as the number nine continued to look the threat he was on this ground eight days ago.
Davis continued to look bright and led a good break early after the interval that ended with a tame shot, and while Luciano Becchio's effort at the other end was fierce, it only struck the bar.
They had the ball in the net with 69 minutes gone, though how it came left a bitter taste for Town; Crowe was grounded when Andy Hughes carried the ball through midfield and passed right for Andy Robinson to send a deflected cross over, which Beckford headed in at the far post.
In defence of referee Chris Foy, there is nothing in the laws of the game to say play should be stopped – Crowe's injury was not to the head, and therefore it was up to Leeds whether they wanted to kick it out or not.
Any team in that position would have done what Leeds did.
Gray threw the dice with a quarter of an hour to play, putting Nicholas Bignall up front with McGleish and giving Davis a run on the right.
The move left the Cobblers with all five of their loan players on the park at the same time, and it was one of them who put the side back in front.
Town won their first corner of the game with three minutes to play and Jackman swirled over an inch-perfect cross which Bignall headed home powerfully.
Bignall may be registered to Reading but he celebrated the goal as passionately as anyone in the ground with an NN postcode.