Cobblers moved to within a place of the play-offs when registering a third straight win at the expense of Cambridge United on Saturday as they prevailed 2-0 winners at a rain-soaked PTS Academy Stadium.
The two teams slugged it out in rotten conditions but while entertainment and quality were both hard to come by on an awful afternoon, Town were ruthlessly efficient and made the most of the opportunities that fell their way.
Harry Smith's cool finish steered them ahead before his cross was diverted into the net by United captain George Taft in first-half stoppage-time, giving the home side a cushion.
The second-half was not a pretty watch as conditions worsened but, for the third time in a week, Cobblers defended doggedly and robustly on their way to a third successive clean sheet, which in turn completed a perfect week.
Keith Curle's side, who have not conceded a goal for 320 minutes, are now eighth and four points off third place in Sky Bet League Two.
After successfully changing shape midway through Tuesday's win at Carlisle, Curle persisted with three at the back for the visit of Colin Calderwood's Cambridge as recent signing Paul Anderson was handed his full debut at wing-back.
Alan McCormack and Smith were also recalled to the starting line-up but Cambridge adapted better to the sodden conditions at the PTS and stroked the ball around with confidence in the early moments.
The combination of a saturated pitch and persistent rain made life extremely difficult for both sets of players and subsequently chances were in short supply in a largely uneventful start to the game.
Visiting stopper Dimitar Mitov was first called into action when tipping over Scott Wharton's header on 18 minutes and Town's defender was denied by the same man at the following corner.
Opposite number David Cornell produced his own flying save midway through the half when reacting quickly after Marc Richards' shot deflected off Paul Lewis.But it was Town who moved in front on 26 minutes.
Cambridge switched off at the back and Smith latched onto Nicky Adams' through pass and was allowed to charge through unchallenged before calmly slotting past Mitov.
Tenacious work from McWilliams almost set Smith away again but Mitov raced off his line and got to the ball in the nick of time as Town began to take a hold of the game.
Cobblers did have a second goal in first-half stoppage-time and the scrappy nature of it matched the increasingly ugly conditions.
McWilliams' pass eventually bobbled its way through to Smith whose attempted cross was diverted into the net by Taft.
Smith was causing all kinds of problems for United's defence and that was evident again shortly after half-time when he out-muscled his man and was only thwarted by Mitov.
The visitors increasingly dominated possession as the second-half unfolded but they were limited to few clear chances, one of which saw Cornell at his best to keep out Richards on his Sixfields return.
United's possession was largely harmless though as Town were in no mood to lose their clean sheet, and they could have had a late third when substitute Andy Williams slashed wide.
Cobblers: Cornell, Goode (c), Turnbull, Wharton, McWilliams, McCormack (Lines 68), Pollock, Hoskins, Adams, Anderson (Waters 58), Smith (Williams 73)Subs not used: Fisher, Hall-Johnson, Harriman, Oliver
Cambridge: Mitov, Knoyle, Taft (c), Dunk, Darling, Dunk, Lambe, Lewis, Ward (Knibbs 71), Smith (Dallas 78), Richards (O'Neil 86)Subs not used: Taylor, Johns, Davies, Burton
Referee: Graham Salisbury
Cambridge fans: 694