The U18s ended their pre-season preparations with a 3-1 friendly win over MK Dons U18s at Moulton College on Saturday morning.
The Cobblers started strongly, as Lewis Gilbert half-volleyed wide before heading over from six yards early on.
Tommy Curry gave the Cobblers the lead on the quarter-of-an-hour mark with a smart left-footed finish into the bottom right corner.
10 minutes later, Courtney Lashley did very well to beat two men on the left and float a deep cross towards the back post, but Lewis Gilbert's header was cleared off the line.
Ewan Clark's shot from the penalty spot was beaten away by the keeper after Liam Cross drove down the right flank and cut back to his midfield partner on the half-an-hour mark.
Jack Connor had a shot saved before he doubled the Cobblers' lead five minutes before the break, tapping in Richie Bailey's cross after the right-back, captaining the side, was found by an excellent cross-field pass from Josh Flanagan.
The first opportunity of the second period came on the hour mark when the Dons' keeper tipped Ewan Clark's free-kick wide as it curled towards the bottom right corner.
The Dons pulled a goal back in the 67th minute, with their forward in on goal, and he tucked a simple finish past Charlie Woods.
Substitute Ethan Lack made an instant impact after coming on with a quarter-of-an-hour to go, capitalising on a loose pass before his powerful shot was blocked behind for a corner.
Less than a minute later, Josh Flanagan restored the Cobblers' three-goal lead, half-volleying into the roof of the net from eight yards after his initial header rebounded back into his path.
Ethan Lack pounced on another loose ball five minutes later, but his attempted chip was denied by the keeper.
Liam Cross hit the post directly from the resulting corner, and the Dons responded with a speculative 35-yard effort that almost caught Charlie Woods out but sailed harmlessly wide.
The last opportunity fell to Tom Scott, who fired over from the edge of the area in the last minute of the game.
The U18s host Peterborough United U18s in their first 2020-21 EFL Youth Alliance League fixture next week.
Cobblers - Berry (sub Woods, 45 mins); Bailey, Dyche (sub Abimbola, 72 mins), Flanagan, Lashley (sub Dylan Hill, 72 mins); Cross, Scott, Clark (sub Gilbert, 86 mins); Gilbert (sub Lack, 72 mins), Connor, Curry.
Goals - Curry (15 mins, 1-0), Connor (40 mins, 2-0), Flanagan (77 mins, 3-1).