The Hatters suffered late heartbreak after their defensive resolve was broken in the 85th minute by Blackburn Rovers.
It was a tough result to take after what was largely an impressive performance from the Town players, who defended resiliently and even had the ball in the net themselves, only to be ruled out for offside.
Manager Nathan Jones made three changes from the last Sky Bet Championship fixture, opting to start Matty Pearson, Glen Rea and Jordan Clark – the latter who scored for Town in the 3-1 Emirates FA Cup defeat against Chelsea.
It was a lively start from the hosts on a windy afternoon at Ewood Park as Sonny Bradley produced a goal-saving tackle to deny Adam Armstrong, who had latched on to a loose ball and charged through on goal before being stopped in his tracks.
The skipper was at it again a couple of minutes later, making an important block to divert Ben Brereton’s shot behind for a corner.
After weathering somewhat of an early storm, the Hatters had plenty of the ball in the first half and created some good openings, though to little avail.
On his 150th appearance for the club, Harry Cornick was the most persistent threat and produced several good crosses into the box, the best of which fell towards Clark, but Thomas Kaminski was off his line quickly to get to the ball first.
Simon Sluga was alert straight away in the second period to save down low from Armstrong as both teams tried to get the better of one another.
It was a half in which both defences were on top form, particularly for the Hatters when Martin Cranie, moments after entering the fray, made a crucial block to deflect Tyrhys Dolan’s shot away from goal.
With 12 minutes remaining, Kiernan Dewsbury-Hall managed to win the ball in midfield and picked out Cornick in acres of space on the right. The former Bournemouth man shaped to shoot but instead passed the ball inside towards Clark, but Rovers managed to intercept and clear.
After Dewsbury-Hall was denied from the edge of the box, against the run of play, Blackburn took the lead in the 85th minute.
Rovers took a drop-ball quickly, Sam Gallagher headed the ball across to Armstrong, who made no mistake to score his 17th league goal of the season.
But the drama was not yet over. Keen to make amends, Luton had an attack of their own to try and forge back into the game and for a split second they believed they had.
With just a minute to go, Dewsbury-Hall’s free-kick was played across the box by Sonny Bradley, Danny Hylton couldn’t get good enough connection on the ball but Cornick lashed the ball high into the roof of the net with the second opportunity, before the linesman raised his flag for offside.
It was a bitter blow for the Hatters, who will hope to earn a more positive result at home to Huddersfield Town next weekend.
Town: Sluga; Pearson (Cranie 72), Lockyer, Bradley (C), Potts; Rea (Nombe 88), Mpanzu, Dewsbury-Hall; Clark (Naismith), Cornick, Collins (Hylton 65).
Subs not used: Shea, Berry, Hylton, Moncur, Naismith, LuaLua, Nombe, Morrell.
Blackburn: Kaminski; Nyambe, Lenihan, Branthwaite, Douglas; Travis, Rothwell (Dolan 61), Downing (Holtby 61); Elliott (Dack 61), Brereton (Gallagher 61), Armstrong.
Subs not used: Pears, Buckley, Evans, Bennett, Magloire.
Goals: Armstrong (85)
Referee: Jeremy Simpson