Don Hutchison and Paul Peschisolido grabbed a goal each as Luton cruised through this Johnstone's Paint Trophy First Round tie.
A poacher's finish from Hutchison and an unstoppable drive from Peschisolido, with his first touch after coming on as a half-time substitute, were enough to see off a Northampton side who hardly threatened Dean Brill's goal.
The Cobblers thought they should have had a penalty when Huboltz went down as he tried to go past Perry, but instead he was booked for diving.
And although Northampton had plenty of possession they never broke through Luton's defence, well marshalled by the impressive Jaroslaw Fojut on his debut.
In fact Brill's first real save came in the closing minutes when he dived to turn a Gilligan drive around the post.
Hutchison opened the scoring on 11 minutes after Calvin Andrew had caused panic in the Northampton defence from a corner separated the two sides at the break, but Luton looked largely in control against a Cobblers side who hardly threatened Dean Brill.
The second came a minute into the second half when Steve Robinson picked up the ball on halfway and surged forward before slipping a neat ball through that split the Cobblers defence wide open. Peschisolido ran on one-on-one with the keeper and smashed the ball into the net before Bunn had a chance to dive.
Kevin Blackwell made six changes from Saturday's starting line-up. Out went keeper David Forde, Chris Coyne, Dave Edwards, Darren Currie, Matthew Spring and Paul Furlong.
They were replaced by Brill, Fojut, Hutchison, Robinson, Ahmet Brkovic and Calvin Andrew.
Northampton started more brightly but Luton had a chance on five minutes. Alan Goodall's pass out of defence was flicked into Bell's path by Drew Talbot and he advanced into the area. His first shot was blocked and his second just over the corner of the bar.
Northampton had little to show for the first period. May had a dipping shot well over Brill's bar on six minutes, Hubertz lashed one well wide at the far post on 29 and Dyer shot high and wide from distance on 33.
The closest Northampton came was when Hubertz put the ball into the net on 38 minutes after being put through from a deflected clearance, but the flag was up for offside.
Luton took the lead on 11 minutes from their first corner of the game. Bell swung it over from the right, Andrew climbed high and got in a powerful header that was blocked on the line but Hutchison was there first to turn the ball in.
A minute later they almost made it 2-0 from a second corner when Brkovic arrived at the near post and his header hit the post and was scrambled away.
There was a scare for Luton on 22 minutes when Bell went off and was replaced by McVeigh.
Talbot's low cross from the right brought a sprawling save from Bunn on 35 minutes but then he failed to pick out an unmarked McVeigh in the six yard box from Robinson's surging run a minute later.
HALF TIME: Luton 1-0 Northamtpon
Paul Peschisolido replaced Talbot at half time as Northampton again started brightly, Johnson firing just wide from distance on 46 minutes.
Peschisolido didn't waste any time, making it 2-0 with his first touch after Robinson picked up the ball in midfield, surged through and slipped the striker in one-on-one with the keeper. Peschisolido blasted the ball inside the post, giving the keeper no chance.
Northampton thought they had a penalty when Huboltz went down as he tried to go past Parry, but the referee booked the striker for diving.
That livened the game up and Northampton had a string of free kicks without threatening Brill's goal.
Peschisolido was on form, harrying the Cobblers defence and on 60 minutes he turned on a throw in from the corner of the box and put a rasping shot just over the far post.
Then he just over-ran Andrew's flick on from a long Brill kick.
McVeigh joined in a put a shot from 20 yards inches past the post as a diving Bunn was well beaten on 61 minutes.
Crowe had a surging run but shot wide of the post on 68 minutes as Northampton worked hard without much to show for it, largely having long shots that did not trouble Brill.
McVeigh then eased his way into the box on the left and clipped a shot that curled just wide of the far post on 83 minutes.
Northampton had a late flurry when Gilligan forced a sharp save out of Brill and then Crowe should have done better, volleying over a dropping ball six yards out with two minutes left.
Morgan and Peschisolido got through and Morgan's shot was just defelcted wide in stoppage time as time ran out for Northampton.
LUTON: Brill, Keane, Fujot, Perry, Goodall, Brkovic, Robinson, Hutchison, Bell (McVeigh 22), Talbot (Peschisolido 45), Andrew (Morgan 86). Subs: Coyne, O'Leary.
NORTHAMPTON: Bunn, Hughes, Doig (Crowe 28), Larkin, May, Johnson, Dolman, Dyer (Gilligan 68), Jones, Russell, Hubertz (Kirk 55). Subs: Holt, Dunn.