Cobblers produced arguably their best performance of the season to date in beating Oxford United 2-1 and climbing out of the Sky Bet League One relegation zone as goals from Ash Taylor and Chris Long did the business at the Kassam Stadium on Saturday.
Jimmy Floyd Hasselbaink named a bold team for this trip across the border and he was fully vindicated by an excellent performance from his side, both in attack and defence, as they registered three well-deserved points to climb to 19th.
If anything, the margin of victory could have been greater after a number of chances went begging but Taylor's early opener and Long's fine solo effort on the stroke of half-time were enough to earn Town both a third straight league victory and also a third win in three seasons at the Kassam Stadium.
The Cobblers were full value for their half-time lead having outplayed Oxford for much of an end-to-end opening period and they should have been more than the one goal in front, scored by Taylor, when Wes Thomas' low finish brought the Oxford.
But Town had their noses back in front within two minutes thanks to Long and they nullified their hosts' threat throughout the second-half to extend their unbeaten run to six games in all competitions.
As expected, Hasselbaink reverted back to a near full-strength team for the visit to Grenoble Road following Northampton's Checkatrade Trophy exertions in midweek.
He made nine changes in all with Lewis McGugan, Matt Grimes and John-Joe O'Toole starting in a midfield three behind Billy Waters, Daniel Powell and striker Long.
Town settled quickly into the game and their dominance of the opening exchanges resulted in the first clear chance as David Buchanan collected Grimes' fine pass and crossed into the middle where Long's poke towards goal was turned behind by Simon Eastwood.
Oxford came straight back in an open and frantic start and only a superb sliding challenge from Brendan Moloney prevented James Henry from getting a clean shot at goal.
And the importance of that invention from the right-back became clear within three minutes. The Cobblers broke, won a corner and with Oxford unable to clear, the ensuing goalmouth scramble eventually fell to Taylor, who somehow squirmed his shot through the mass of bodies and over the line for the defender's third goal in six games.
The visitors took confidence their good play and deserved lead, and they were close to adding a swift second but O'Toole couldn't get enough power on his header from McGugan's free-kick before McGugan himself forced Eastwood into a fine fingertip save with a 25-yard shot.
Town lost Powell to injury midway through the first-half, replaced by Dean Bowditch, but that didn't disrupt their rhythm and they remained on the front foot as Grimes' shot was blocked after silky skills by McGugan.
Dominating possession wasn't an issue for Oxford, who strung together several intricate passing moves, but their end product lacked quality and penetration to really hurt Northampton.
However, that was to change in an explosive end to the first-half. Town switched off after a lengthy delay, caused by an injury to Curtis Nelson who had to be stretched, and United capitalised with Henry slipping through Thomas who drilled unerringly into the bottom corner.
That represented Oxford's first goal against their cross-border rivals in over 400 minutes and it could have knocked the wind out of Northampton's sails but, instead, they hit back instantly, requiring only 105 seconds to restore their advantage.
After winning possession in the Oxford half, Long charged forwards, skipped past Aaron Martin and clinically shot through Eastwood.
The impressive Payne struck a free-kick straight into the wall in what continued to be an end-to-end half but United were unable to find a second equaliser in any of the five added minutes before half-time.
Northampton started the second-half well and their quest for a two-goal margin was so nearly achieved when Long got behind the Oxford defence and squared for Waters, who would have had a tap-in had it not been for Ricardinho's vital touch.
By this stage, the visitors had created enough chances to be comfortable but their failure to convert kept Oxford in the game very much in the game, and the hosts went close to a leveller with Joe Rothwell volleying just wide of Matt Ingram's right-hand post.
The second period was a more subdued, cagey affair than the first and generated far fewer opportunities in front of goal, though Ingram did have to keep out Thomas' header.
Ingram's workload became heavier as the clock ticked down as he also also beat away Rob Hall's stinging effort and then tipped over from the same man while Thomas dragged a shot marginally wide.
But, if truth be told, Oxford created no more than half chances and, once three minutes of injury-time had passed, they could have few complaints over the final outcome.
Oxford: Eastwood, Tiendalli, Nelson (c) (Martin 42), Hall, Ledson, Thomas, Henry (Fernandez 81), Rothwell, Ricardinho, Mousinho, Payne (Obika 64)
Subs not used: Shearer, Ruffels, Mowatt, Carroll
Cobblers: Ingram, Moloney, Taylor, Pierre, Buchanan (c), Grimes, McGugan, O'Toole (Foley 57), Waters, Powell (Bowditch 19), Long (Richards 90)
Subs not used: Cornell, McGivern, McWilliams, Crooks
Referee: Kevin Johnson
Cobblers fans: 1,125