Northampton were quick out of the traps and Mark Cousins was forced into a sensational save in the 8th minute, plucking Andy Williams’ goalbound effort over the crossbar.
Josh Walker then made a great run through the Cobblers defence before setting up the trialist who curled an effort at goal, forcing a save.
The deadlock was broken midway through the first half when Andy Williams rose highest to head home Hoskins’ cross.
Cousins was called into action again, saving a low effort from Whaler. Then, Charlee Adams, playing in an unfamiliar position at centre-half, was alert to the danger and cut out a dangerous two-on-one opportunity for the hosts.
Northampton doubled their lead on the half hour, Hoskins placing the ball into the bottom corner after good link-up play from the midfield.
Changes were made at half time but the Bees still found life difficult against a strong, regimented Northampton back line.
On the hour, Tarpey battled hard to win the ball in the box, managed to get a shot away out of nothing but hit the side netting from a tight angle.
The goal of the game came in the 78th minute, Billy Waters’ half volley cannoned off of the bar, against the post and into the helpless Cousins’ goal.
With the last kick of the game, Dave Tarpey lined up a freekick from 30 yards out which the home ‘keeper could only gather at the second attempt.
Barnet – Cousins, Johnson, Adams (Barham, 89), Coulthirst, Sparkes (Mason-Clark, 45), Boucaud, Fonguck, Trialist (Kyei, 84), Walker (Tarpey, 45), Tutonda (Payne, 76), Sweeney.
Unused – Azaze, J. Taylor.
Attendance – 883 (46 Barnet)
Referee – Dean Whitestone