The Hatters' season ended with an unfortunate first defeat in seven matches at QPR, on an afternoon when Kiernan Dewsbury-Hall signed off from his loan with his third Town goal in another magnificent performance from the Leicester City loanee.
Nathan Jones' side finished 12th in the Championship, the position they started the day in, but despite a dominant first-half performance, couldn't pull off the win that could have taken them level with the hosts, who ended the day where they started it, in ninth place.
Manager Nathan Jones made three changes, with George Moncur starting for the first time since defeat versus Norwich City in March, coming in for Dan Potts to enable a change of formation, with Harry Cornick and Pelly-Ruddock Mpanzu also included in the starting XI.
The game started with a yellow card inside the first minute, with Rangers striker Charlie Austin going into referee Tony Harrington's book for a high challenge on Matty Pearson with just 35 seconds on the clock.
Town almost took the lead in fluke style when Harry Cornick tried to slip Elijah Adebayo into the box, but Jordy De Wijs intercepted and his ricochet took the ball past wrong-footed keeper Seny Dieng, but a foot the wrong side of the post from a Town point of view.
Moncur attempted a curler, just off target, before on-loan Fulham midfielder Stefan Johansen threaded Chris Willock into the Town area, but the former Arsenal and Benfica youngster flashed his shot across Sluga and out for a throw-in on the far side.
Soon it was the Hatters' turn to attack again, Cornick picking out Moncur, who might have volleyed Huddersfield and Reading in the Cup-style, but chose to have a touch and check back. Once again, his curling effort was wide, before Adebay drove into the hosts' area after a fine ball from Dewsbury-Hall, but dragged his shot wide of the near post.
Rangers had the lead on 20 minutes though when Austin found space in the box to control Lyndon Dykes' knock-down and finish calmly past Sluga from seven yards out.
Town should have been level five minutes later when Dewsbury-Hall broke through the centre of the pitch after trading passes with Kal Naismith just outside the Hatters' area. The midfielder spread the ball left to Moncur, who took a touch before hitting a left-footed shot that was deflected just wide of the near post by a sliding Rob Dickie.
Fro the resulting corner Cornick saw a shot from outside the box go just wide, again with the aid of a deflection, before Dewsbury-Hall had the same result with a left footer from 25 yards as the Hatters asked all the questions.
It was from another corner, and Cornick's blocked shot, that Rangers broke quickly down the left, with the covering defender James Bree doing brilliantly to slide across and block Willock's shot as he burst past Pelly-Ruddock Mpanzu just before the half-hour.
Captain Sonny Bradley came closest to levelling in the 41st minute, meeting Dewsbury-Hall's free-kick, after the midfielder had been fouled himself by Dykes, with a first-time volley that Dieng somehow managed to push onto the post.
The equaliser finally came in the 43rd minute, and it was that man Dewsbury-Hall, who had been involved in everything from a Town point of view during the first half. The Leicester man played Moncur in on the left once again, and when his shot was saved by Dieng, it rolled into the path of Dewsbury-Hall, who with his weaker right-foot, placed the ball into the bottom corner from just inside the box.
It was no less than the Hatters deserved, and Rangers boss Mark Warburton made a change at the break, bringing on Sam Field in place of Dykes, who had been on the wrong end of a late challenge from Glen Rea that had earned the Town man a yellow card just before the whistle.
QPR were back in front on the hour when Ilias Chair opened up the Hatters defence and played Johansen into the box to lift his effort over Sluga.
Austin chanced his arm from 25 yards in the 66th minute, but his effort flew high over Sluga's bar and it would be the on-loan West Brom striker's last action, as he was withdrawn for the R's other goalscorer in their win at Kenilworth Road in January, Macauley Bonne.
Sluga was at full stretch to divert a Willock shot behind for a corner, just before Jones made a triple change in the 71st minute, bringing on Luke Berry, James Collins and Kazenga LuaLua for Rea, Moncur and Cornick.
Collins and Berry were soon combining to create a chance for Naismith to take aim from 25 yards, but his curling effort wouldn't come down quickly enough to trouble Dieng's goal.
As we prepared to enter the last ten minutes, Berry pulled a ball back along the edge of the box for Collins to strike at goal, but his shot was blocked by Yoann Barbet, then Albert Adomah sent a free-kick over Sluga's crossbar.
Jones threw Dion Pereira on for his Town debut in the 86th minute, replacing Bree, and with his one real passage of play he beat his man into the box and cut the ball back for Collins, whose shot was blocked.
Rangers went up the other end and added a third with Adomah's injury-time tap-in, and the Hatters didn't deserve a season to remember to end that way, but they could hold their heads high.
On to 2021-22, a third season in the Championship and hopefully the return of our wonderful supporters.
Thank you the players, to the manager, his staff and all Hatters at Home for your support throughout. You have all been amazing.
Town: Sluga; Bree (Pereira 86), Pearson, Bradley (C), Naismith; Rea (Berry 71), Mpanzu, Dewsbury-Hall; Cornick (LuaLua 71), Moncur (Collins 71); Adebayo.
Substitutes: Shea, Cranie, Potts, Tunnicliffe, Berry, Collins, LuaLua, Morrell, Pereira.
Queens Park Rangers: Dieng; Dickie, De Wijs, Barbet; Kakay, Chair, Willock, Johansen, Wallace; Dykes (Field 46), Austin (Bonne 66).
Substitutes: Walsh, Bonne, Field, Thomas, Cameron, Carroll, Hamalainen, Bettache, Adomah.
Goals: Austin 20, Johansen 60
Referee: Tony Harrington