Cobblers reached round three of the FA Cup for only the second time in 14 years after a relatively routine, if not always comfortable, 3-1 victory over non-league Notts County on Sunday.
Scott Wharton's fourth goal in three games handed Town the perfect start and their place in the third-round draw looked safe when Vadaine Oliver was on hand to make it 2-0 midway through the first-half.
County, currently 11th in the National League, were admirable opponents and did not go away quietly but Cobblers' place in Monday's draw was secured by Harry Smith's second-half header.
And despite Kyle Dennis scoring a late consolation for the Magpies, Keith Curle's side were not to be denied their seventh win in eight games across all competitions.
Saturday's FA Cup tie marked the first of three games in six days for the Cobblers but Curle didn't mess about with his team selection and made only one alteration from last week's league victory over Grimsby Town.
That change came in goal as Steve Arnold replaced David Cornell, and Curle's side flew out of the blocks with a goal just three minutes in, Wharton ghosting in at the back post to powerfully head Nicky Adams' corner into the net.
That set the tone for a lively and action-packed opening 10 minutes and County almost replied straightaway but Regan Booty scuffed his shot when in space just 12 yards from goal.
From nearly levelling, the visitors were then fortunate not to fall further behind as Sam Slocombe kept out Sam Hoskins with the rebound hitting Magpies defender Ben Turner and coming back off the post.
County played some decent stuff in possession but any promising moments in attack were undermined by their defensive fragility and with just 24 minutes on the clock they had a mountain to climb.
That's when the home side added to their lead as tenacious work by Adams got Town on the front foot before Hoskins' peach of a cross from the left-wing gave Oliver a simple finish beyond Slocombe.
A wonderful one-two between Hoskins and Lines teed up the former for a shot, parried by Slocombe, while Hoskins' overhead kick was scrambled away before Goode turned Adams' cross wide of the near post.
The Cobblers became sloppy and untidy in the second-half and County, roared on by a strong following, didn't give up hope with Turner heading over and Enzio Boldewijn rippling the side-netting.
They went closer still when Wes Thomas squandered a golden chance to halve the deficit as he headed over with Arnold nowhere to be seen.
But despite playing second fiddle, the game was up with 14 minutes to go when Cobblers rubber-stamped their place in the next round through substitute Smith, who nodded in Hoskins' high cross.
Slocombe thwarted Williams and Smith's header was cleared off the line but the damage had well and truly been done - despite Kyle Dennis pulling one back with eight minutes left.
Things may have got interesting had Dennis converted a second chance moments later but Arnold kept out his shout and made sure there were to be no late scares for the Cobblers.
Cobblers: Arnold, Goode (c), Turnbull, Wharton, McCormack (Warburton 77), Lines, Hoskins, Adams, Anderson (Watson 68), Oliver (Smith 62), Williams
Subs not used: Cornell, Hall-Johnson, Harriman, Pollock
County: Slocombe, McCrory, Rose, Turner, Thomas (Dennis 77), Doyle (c), Boldewijn, Wootton (Tyson 84), Rawlinson, Booty (Shields 45), Brindley
Subs not used: Kelly-Evans, Bakayogo, Osbourne, Kean
Referee: Paul Marsden
County fans: 1041