The Hatters ended their campaign from Kenilworth Road with defeat after suffering a 2-0 loss to champions Northampton at Sixfields.
Zander Diamond opened the scoring just four minutes in, before John Marquis doubled the advantage before half-time.
Cameron McGeehan and Joe Pigott had goals disallowed, with the Town unable to spoil the champions’ party in the Midlands.
There was more bad news for the Hatters when Danny Green was caught late to be stretchered off with what looks to be a serious injury for the Town midfielder.
Nathan Jones made two changes from the draw with Newport County AFC, drafting in Jonathan Smith and Cameron McGeehan as Alex Lawless and Josh McQuoid took places on the bench.
Only four minutes had passed when the Cobblers delivered a sucker-punch through Diamond, meeting Danny Rose’s right-wing corner to put a bullet header past Justham.
But the Town had early sighters of their own through Green, teed up by Dan Potts to fizz powerfully, but ultimately wide of Adam Smith’s goal.
That proved the last action of Green’s game, caught late by Josh Lelan, who escaped with just a caution, attended to with oxygen and a stretcher as he was carried off with what looked like ligament damage.
With McQuoid on in Green’s place, the Hatters came agonisingly close to an equaliser. Smith showed great awareness to feed Ruddock down the right, and his ball in met Pigott on his own in the middle, only for his header to fly away high and wide from goal with no home defender around.
It was the best chance of the half for the visitors, with Northampton doubling their lead just six minutes later through Marquis. The striker couldn’t miss from a matter of yards after Ricky Holmes’ cross flicked John-Joe O’Toole on the way through, giving the hosts a two-goal half-time advantage.
It was a better start to the second half for the Hatters though, now opting to have two in attack following the introduction for Jack Marriott in place of Olly Lee.
The switch to 4-4-2 brought the Town back into the game, and the scoreline almost reflected that when Pigott struck the base of the post following good work down the right flank.
The same man dragged an effort wide five minutes later, profiting from Marriott’s miscontrol after being slipped through by McQuoid on the edge of the Cobblers box.
The hosts were enjoying their party, however, with neat intricate passing earning cheers from the hope support, almost culminating in Hoskins finding the back of the net, with Holmes also chancing his arm soon after.
The Hatters kept pushing, and almost struck a late consolation when substitute Jake Howells was fouled on the edge of the area. Sheehan stepped up to take the free-kick, curling beyond the wall but also passed the far post as the Town ended their away travels with a defeat.
Hatters: Justham, O'Donnell, Sheehan (c), Rea, Potts, Smith, Lee (sub Marriott 46), McGeehan, Ruddock (sub Howells 86), Green (sub McQuoid 21), Pigott
Subs not used: King, Lawless, Benson, Musonda,
Attendance: 7746, including 841 following the Hatters. Thank you for your excellent support on our travels this season!