Steve Cooper’s men have now suffered their first league defeat since January, at the expense of their fellow promotion-pushing hosts.
The hosts had made two changes to the side that lost 2-0 at Huddersfield last time out, with Reece Burke and Robert Snodgrass entering the side in place of Pelly Ruddock and former Forest captain Henri Lansbury.
Story of the game
In a game with a technical issue-based kick-off delay, it was Luton who took the game to their guests early on, with Elijah Adebayo forcing an early save from Brice Samba after finding himself in after just five minutes.
The chance managed to level out some of the early pressure in the game, with no clear cut chances being carved out in the next ten minutes; Fred Onyedinma had a go from range and Djed Spence raced into the box before being tackled well by Sonny Bradley.
Grabban tried to whip one towards goal from 30 yards five minutes later, but his effort skewed very high and wide of the mark as the game mellowed out.
Luton managed to break the deadlock from the spot in the 36th minute, after the referee adjudged Jack Colback to have been struck by the ball on the arm in the area. Kal Naismith stepped up and coolly slid it home down the middle.
Forest started to battle back from that point, and had the ball in the net through Spence after Onyedinma slipped up, but the flag was raised.
The game threatened to boil over at several occasions from there, with a scuffle on the touch line resulting in a yellow card for Davis.
Naismith found himself free from a corner on the 66th minute, but stabbed his free header into the ground and over the bar.
Just moments later, Brennan Johnson floated a gorgeous ball over to substitute Zinckernagel at the back post, but he also fluffed a free header into the gloves of Shea.
The Reds began to pile on the pressure, and a long-range Zinckernagel attempt rattled the post moments before Johnson forced another Shea save from the rebound.
Adebayo saw a chance to wrap up the points after breaking in on the left, but forced a strong stop from Samba at his near post.
There was to be no extra drama, however, and Luton Town held on for a massive three points in the battle for the play-offs.