Rovers went fourth in the table with a first-minute Harry Anderson goal proving the difference at Sixfields.
Rovers had been able to name an unchanged starting XI for the fourth consecutive game. The only change in the matchday squad comes in the form of Leon Clarke who replaced Luke Thomas on the Gas bench.
The Gas were in dreamland after 38 seconds at Sixfields as Anderson latched onto a dreadful backpass to fire the Gas ahead. Culprit Jon Guthrie could only watch in horror as Anderson showed composure from a tight angle to slide the ball past Liam Roberts give the visitors the lead.
The wind was as blustery as the sun was bright and Rovers were enjoying some early dominance with the ball that their flying start afforded them. In the 15th minute, there was a long stoppage as Northampton's Magloire, who had been penalised for a foul on Finley, fell awkwardly and needed oxygen, before being stretchered off.
The game resumed with a Gas free-kick, which Evans took short to Coutts, who found Elliot Anderson, but the referee blew as he looked to shoot. A minute later, Evans jinked his way to the byline but ran out of pitch before he could cross. The midfielder then gave away a free-kick for a push but the Cobblers couldn't capitalise.
James Belshaw almost provided an assist in the 24th minute as he raced from his box to clear, finding Harry Anderson free down the middle, but his touch just let him down and Horsfall cleared. Hoskins headed over for Northampton in the 25th minute and the hosts were soon back on the attack as Guthrie crashed a header onto the bar from a Hoskins free-kick. A narrow escape for the Gas, but they approached the half-hour mark a goal to the good.
Northampton were beginning to find some rhythm and Connolly was forced to head clear from a teasing Pinnock cross in the 31st minute. A Coutts pass was intercepted but Taylor read the danger well to clear. Referee Langford was having to contend with a lot of niggly fouls from both teams as the play stuttered from box to box.
Lewis thought he'd equalised in the 39th minute, but a flying Belshaw had other ideas, tipping acrobatically over. Finley then won a corner at the other end, with Coutts header being deflected behind for another. from it, Elliot Anderson ran past two defenders into the box, but his cross was cleared for a third corner. Finally, Northampton were able to clear their lines, with the Gas threatening a second.
The home fans were getting agitated at every decision that went against them as Rovers safely navigated their way to the interval with their lead intact. Rovers began the second half attacking the away end in front of their 1,388 travelling supporters. Evans was soon on the attack but kicked it straight behind whilst looking to win a corner. Rovers were on the front foot, though, and looking to further frustrate their hosts.
Coutts defended well to stop the home side down the right in the 50th minute. The ball fell to McGowan in a dangerous position, but he ballooned his cross well over Belshaw's bar. The Gas raced up the other end and Finley's inviting cross was cleared behind for a corner. Unfortunately, Evans lost his footing whilst receiving a pass from Elliot Anderson.
A great cross from Luca Hoole in the 56th minute caused panic in the home box and Anderton nearly profited from a loose ball but the ball was scrambled away. Collins was flagged offside two minutes later as the hosts continued to play a high line. Elliot Anderson won a free-kick in the 60th minute and McGowan became the first player to be cautioned. The free-kick was wasted though, with most of the Rovers forward line being flagged offside.
Finley charged down a clearance in the 63rd minute, strode forward and curled a shot straight at Roberts, before Elliot Anderson cleverly won a corner. From it, he took on his man and fizzed a low effort that Roberts was again equal to.
The crossbar came to Rovers' rescue again in the 64th minute; Belshaw diving helplessly as Pinnock's shot rebounded back into play.
Finley was shown a yellow for a late challenge in the 68th minute. The game was becoming stretched now and Rovers were grateful for a lull in play thanks to a yellow for Horsfall for sliding in on Belshaw, who required treatment. The keeper was back in the action again in the 75th minute, picking up a booking for taking too long to take a free-kick.
Sowerby thankfully overhit a pass in the 77th minute with Rovers out of shape at the back. Hoole's clearance was then charged down, with the defender having to race back and concede a corner against the tricky Pinnock. Referee Langford blew for an infringement and a Rovers free-kick.
Play was now frenetic. Elliot Anderson looked to go round the 'keeper but the ball was snatched away from his feet. Northampton immediately counter-attacked and Connolly was cautioned for a professional foul. Elliot Anderson was hacked down in the 82nd minute as he went round McGowan; Evans' whipped free-kick rippled the side-netting.
Pinnock's long throw-ins were a constant menace but, from one in the 85th minute, Rovers streaked clear and Harry Anderson went rampaging down the right. Unfortunately, his cross was just too far in front of Aaron Collins. Harry Anderson then won a free-kick on the right in the 87th minute. Elliot Anderson's attempts to run down the clock were thwarted and Northampton cleared.
Rovers won an 89'th-minute corner as the fourth official indicated five additional minutes. Taylor was booked in the first of them, for kicking the ball away. Pinnock was then cautioned for the hosts for throwing the ball into the ground as he contested a decision.
Collins had the ball in the net after 94 minutes, but the linesman had already flagged offside against Evans. Moments later, referee Langley blew to signal a great away performance and a vital three points in the promotion race.
Next up for Rovers is a long trek to Carlisle next Saturday, March 26th for a Sky Bet League Two fixture.
NORTHAMPTON TOWN: Liam Roberts, Aaron McGowan, Jack Sowerby, Jon Guthrie, Fraser Horsfall, Sam Hoskins, Paul Lewis, Mitch Pinnock, Tyler Magloire, Joseph Mills ©, Louis Appere.
Subs: Michael Harriman, Beryly Lubala, Chanka Zimba, Benny Ashley-Seal, Jonny Maxted, Peter Abimbola, Danny Rose.
ROVERS: James Belshaw, James Connolly, Sam Finley, Aaron Collins, Elliot Anderson, Paul Coutts ©, Nick Anderton, Connor Taylor, Harry Anderson, Antony Evans, Luca Hoole.
Subs: Leon Clarke, Trevor Clarke, Harvey Saunders, Cian Harries, Glenn Whelan, Jed Ward, Ryan Loft.
Referee: Oliver Langford.