The Hatters slipped to a third successive defeat as goals from Scott Brown and Terry Gornell gave Accrington all three points from their trip to Bedfordshire.
Brown tapped home from Josh Windass’ pull-back midway through the second period, before Gornell secured the game with a glanced header from Tariqe Fosu’s cross.
It was a third defeat in a row without scoring at Kenilworth Road, leaving a slim chance of the Hatters reaching the League 2 play-off places this season.
Nathan Jones made four changes from last week’s Stevenage defeat, drafting in Elliot Justham for Jonathan Mitchell, who returned to Derby during the week, while Scott Cuthbert had to sit out with injury.
Pelly Ruddock, Dan Potts and Josh McQuoid – in for just his second start under Jones – also took places in the starting XI, while Alan Sheehan took the captain's armband.
The Hatters started electrically at Kenilworth Road, playing with a sharpness missing from recent weeks as Jack Marriott went close twice in the first ten minutes.
The striker could only fire straight at Ross Etheridge from well inside the area, stinging the palms of the Accrington keeper with just eight minutes played. He repeated the dose two minutes later, but this time McQuoid was on hand to seemingly touch home, only for his five-yard shot to sail harmlessly over the bar.
But Stanley came back and showed their promotion credentials, testing Justham through Windass’ long-range strike which the Hatters stopper did well to push away from danger.
It was an entertaining end-to-end encounter for most of the half for a Town side continuing their diamond formation, operated by Cameron McGeehan behind the strikers.
And it was that man next to have a chance, hitting Jonathan Smith’s cutback first time but without meaningful contact as it trickled past the far post.
The pace quelled on the approach to half-time, bringing the visitors back into the game, first with Sam McConville’s zipping ball across the six-yard box, followed by Gornell nodding over the bar.
Yet despite the promise, both sides went to the break goalless, making it nine successive home games the Town have failed to score in before half-time.
And moments into the second half, the Hatters were behind. Windass was allowed to travel down the right flank, picking out Brown in the area who had a simple task to touch past Justham and send Accrington in to the lead.
Bidding for an immediate response, the Town regained some composure thanks to neat one-touch passing that came close to releasing Ruddock through on goal in the middle.
The Hatters were unable to create many clear-cut opportunities, with their chances dealt a blow when Marriott was forced to hobble off on the hour mark, but the introduction of Paul Benson gave the hosts an aerial dimension, as the striker met Potts’ right-side corner to head narrowly over Etheridge’s crossbar.
Ruddock’s pace remained a constant threat as the Town threw on Zane Banton for his first appearance of the season, still trailing by the Brown goal with 20 minutes remaining.
While the Hatters kept pushing, chances were not hugely forthcoming, despite Ruddock blasting purposefully high and wide from a narrow angle.
With Banton now on the pitch, the Town and the crowd responded to the teenager’s pace, posing questions of the Accrington defence within moments of coming on.
But the Hatters were dealt a sucker-punch six minutes from the end. Substitute Fosu jinked his way past O’Donnell, whipping in a cross which Gornell flicked beyond Justham and into the far corner.
Fosu almost made the scoresheet himself with an incredible run, ghosting past four Hatters players before firing past a rooted Justham but, thankfully for the Hatters, also the post.
Youth team captain Frankie Musonda received a warm welcome as he joined the action, but he couldn't prevent the Hatters from a tenth defeat at Kenilworth Road this season.
Hatters: Justham, O’Donnell, Sheehan, Rea, Potts, (sub Musonda 85) Smith (sub Banton 73), Lee, Ruddock, McGeehan, Marriott (sub Benson 62), McQuoid
Subs not used: King, Lawless, Justin, Pigott
Attendance: 7467, with 123 backing Accrington