Cobblers once again demonstrated their penalty-taking prowess on another drab evening in the Checkatrade Trophy as they scooped two points from Tuesday's game at rivals Peterborough United.
A game woefully short on quality and entertainment ended 1-1 in normal time, and it was Town who gained the extra point when winning the shoot-out 4-2.
David Cornell saved two United spot-kicks and with Matt Grimes, Alex Revell, Marc Richards and Billy Waters all scoring, Northampton, as they did against Cambridge last month, came away from the ABAX Stadium with two points, meaning victory over Southampton in their final group game will send them through to the knock-out stage.
In truth, the game itself was a dull and sometimes painful affair but Town did at least end their long goal drought when Posh captain Jack Baldwin diverted into his own net 11 minutes from full-time, cancelling out Danny Lloyd's first-half opener.
Sam Foley and Lewis McGugan both made their debuts in a much-changed Cobblers team that also included Cornell, Yaser Kasim and Waters.
But there was no place in the squad for David Buchanan, who missed only his second game since signing for the club in 2015, while the bench included two academy players.
One of those was the younger brother of Shaun McWilliams, 16-year-old Camron, who became the first player born this millennium to be involved in a Northampton match day squad.
A brilliant recovery tackle from Ash Taylor prevented Idris Kanu from giving Posh an early lead as the home side edged the opening exchanges.
Danny Lloyd's free-kick had to be beaten away by Cornell and Michael Doughty shot wide from distance in a mostly lifeless first-half that failed to generate much excitement.
Northampton were reduced to speculative efforts from range with Conor O'Malley collecting Waters' deflected shot before Foley fired high and wide.
It was not until the closing moments of the half that the game came to life.
The Cobblers were first to go close when McGugan burst into the box but his shot was turned behind by O'Malley and, from the subsequent corner, Posh opened the scoring at the other end.
O'Malley came out to collect and quickly launched a long kick forward to the feet of Miller and after his shot was fumbled by Cornell, Lloyd was there to put away the rebound.
That gave Posh the lead going into half-time and it was a lead they never looked like surrendering for much of a drab second-half that was desperately short on quality.
Daniel Powell blazed woefully over from range and O'Malley easily saved from McGugan, while Cornell was alert to tip Lloyd's free-kick around the post.
It seemed the second-half was drifting towards an inevitable conclusion but, much like the first, a flurry of action brought the game to life and this time it was Town who profited.
After O'Malley tipped Marc Richards' shot crashed onto the crossbar and behind for a corner, Kasim's set-piece was diverted into the net by Baldwin to bring the visitors level.
It wasn't all good news for Town though as Brendan Moloney was taken off with a late injury, and Posh then nearly won it through late efforts from Lloyd and Jack Marriott.
But it went to penalties and the Cobblers, like they did against Cambridge, scored all of their spot-kicks to earn the extra point.
Posh: O'Malley, Shephard, Hughes, Tafazolli, Baldwin (c), Miller (Marriott 66), Lloyd, Lopes, Kanu, Doughty, Grant
Subs not used: Tyler, Forrester, Penny, Anderson, Cartwright, Penfold
Cobblers: Cornell, Moloney (Revell 89), Taylor, Pierre, Smith, Kasim, Foley (Grimes 75), McGugan (Bowditch 70), Powell, Waters, Richards (c)
Subs not used: Ingram, Hanley, McWlliams, Gillard
Referee: Gavin Ward
Cobblers fans: 151