After the highs of last weekend's win at Norwich came the low as the Town slipped to a disappointing defeat at Barrow.
The hosts, with the worst home record in the division, were full value for their victory, defending their fifth-minute goal given to them from striker Adam Boyes.
In truth the Hatters were indebted to a series of fine stops from Mark Tyler to keep the score down to just one as the Town struggled to create a clear-cut chance all afternoon.
And, as the Town fell further behind their pursuit of the leaders, their misery was compounded in injury time when Lathaniel Rowe-Turner was given a straight red card.
Paul Buckle made a total of six changes to the side that lost at Grimsby in the Trophy, and two from the team that beat Norwich seven days ago, with Steve McNulty and Dave Martin given their debuts.
But, the Hatters' dreadful start saw them go a goal behind on five minutes. Greg Taylor's attempted back-header was seized upon by Boyes who was on hand to lob the ball over Tyler from 12 yards.
Hurt, the Town were almost level three minutes later when Ronnie Henry, up in attack, drove a low shot from 15 yards that Barrow stopper Danny Hurst did well to keep out. The Hatters skipper was first to the loose ball to send an inviting cross for Jon Shaw, but before the centre-forward could nod home, Bluebirds right-back Matt Flynn headed clear.
The Hatters were having their fair share of the ball, and on 23 minutes a dangerous cross from Henry almost found Martin in the six yard box but he was crowded out by the Barrow back-line and Hurst was able to collect.
Barrow, beaten 6-1 by the Town at Kenilworth Road three weeks ago, weren't content on just one goal, and the Hatters' wall did their job on 25 minutes to stop a well-hit free-kick from the edge of the penalty area before the Hatters broke up the other end and a tidy move cumulated with a Taylor shot blocked.
Slowly the Hatters were finding their passing game, and a fine pass upfield by Alex Lawless found Andre Gray sprinting through on goal. Goalkeeper, defender and Gray all converged at once which allowed the Town striker to lob an effort goalwards, but the ball dropped, after an age in the sky, on the roof of the net.
The two Barrow men who had collied with one another required three minutes of treatment and, as half-time approached, Hurst kept out a stinging low drive from Gray on 45 minutes.
However, as four added minutes were shown by the fourth official, the Town had two crucial saves from Tyler to prevent the Bluebirds going 2-0 up. Firstly he stopped a shot from Danny L Rowe from close range before doing even better to smother a shot inside the six yard box from goalscorer Boyes in the fourth added minute.
Buckle introduced Scott Neilson at the break for Arnaud Mendy in a move that saw Lawless move inside to partner Jonathan Smith in the centre of midfield and the Town substitute had a sight of goal two minutes after the restart but his half-volley from the edge of the box was deflected and Hurst was able to collect under pressure from Shaw.
Gray, who had cut a frustrated figure all afternoon having got little change of the Barrow defence, cracked an effort out of no-where off the outside of the post from an ridiculously narrow angle on 51 minutes before positive play from Neilson set-up Martin to cross from the left but Gray could not get on the end of the winger's pass.
But the Town were struggling to create a clear-cut chance and they had Tyler to thank once more on 62 minutes to keep out a low effort from Rowe that was scuttling towards the bottom corner.
As time ticked away the Hatters made their second change, introducing last Saturday's goal hero Scott Rendell for Shaw with 20 minutes left.
Neilson continued to be the Town's best outlet for a chance and he was denied by a good piece of defending by James Owen on the edge of the penalty area on 73 minutes when he looked certain to fire goalwards.
Barrow continued to defend well and a brave block from left-back Gavin Skelton stopped a fierce low shot from Lawless that was heading goalwards on 77 minutes.
However as the continued to tick down the Town failed to call Hurst into any meaningful action and to add insult to injury Rowe-Turner was sent-off in the third minute of stoppage time following an off-the-ball altercation with Boyes – and proved the last action on an afternoon disappointment.