Despite numerous chances created by both sides, the scorers were untroubled at the break. The home side had the better of the goal-scoring opportunities in the first period, Captain Roger Johnson bringing a great save out of ex-Arsenal keeper Lee Harper, before highly sought after hit-man Nathan Tyson fired over having been put clean through by a delicious header from striker partner Tommy Mooney.
Johnson missed an easy chance on 37 minutes, before the Cobblers best moment of the first half. Martin Smith rendered the Chairboy's custodian useless as Smith's chip came back off the home crossbar and Argentine youngster Sergio Torres fired over a minute before the break as a lack of clinical forward play meant the home side were unable to press home their advantage.
Tyson blasted wide of the far post on 52 minutes, latching onto a slide rule pass from Johnson, but as the cavalry arrived from midfield Tyson failed to trouble Harper. The Cobblers took the lead against the run of play on 57 minutes following the second corner in as many minutes, the ball being laid back to Chris Doig who finished neatly in the corner.
Three minutes later Wycombe were hit on the break. Josh Low was released down the right, his cross was pinpoint, Junior Mendes' header crashed against the bar and Smith, following up, made no mistake to double his sides' advantage.
Charlie Griffin, one of three second half substitutions made by John Gorman following the second goal, headed over with a free header having been picked out by Danny Senda's cross.
Scott McGleish made it game, set and match on 80 minutes for Northampton. Jason Crowe floated in a ball and McGleish ran on and beat Frank Talia with ease.
Joe Burnell headed in a consolation goal from a Clint Easton corner seconds into added-on time.