Ossett committed the classic smash and grab raid to confirm their status as a bogey side for Matlock as Adam Clayton fired in a last minute winner.
The Gladiators had dominated much of the game, but they wasted their chances. Ossett had two worthwhile opportunities, took one of them and stole the points.
Lee Featherstone earned a recall to the starting line up replacing the injured Lee Stratford, while there was good news as Mark Haran was fit enough to partner James Lukic in central defence. The pair looked every bit the team that Mark Atkins had envisaged when he signed them in the summer.
Jamie Jackson was out with a groin injury, so the substitutes bench was shorn of any attacking options. The starting eleven would have to find the goals needed to win the game.
Unfortunately for Matlock, the shooting boots had been left in the dressing room. Leading scorer Ross Hannah would be particularly disappointed as he could and probably should, have finished with a hat-trick. Liam King had a strike ruled out in the first half and Dene Cropper struck the post after the break, but given all of their supremacy, Matlock failed to work goalkeeper Liam Sutcliffe enough. From that viewpoint, the sucker punch of a goal against the run of the play was perhaps predictable, and it came when Matlock had no time to redeem themselves.
Matlock's first chance came in the 4th minute when Featherstone played in Hannah from the left only for the former Belper striker to fire directly at Sutcliffe.
Ossett replied with Ross Hardaker crossinmg from the left but Matlock had the situation well controlled and Paddy McGuire turned a shot well wide.
But it was mainly Matlock and on 11 minutes, Featherstone gained possession well to find Cropper who in turn set up Hannah for a decent shooting chance, but he dragged his shot wide of the back post.
Matlock were sometimes too impatient to find a breakthrough, constantly falling foul of the assistant's offside flag, but they did find a way through on 20 minutes but Sutcliffe saved well from Hannah after Scott Brough had manufactured the chance.
A diving header from Andy Lee was again comfortably wide in a rare Ossett attack before the action moved swiftly to the other end as Ben Algar fired off target from Cropper's head down off a Brough centre.
But the Blues came within a whisker of taking the lead on the half hour. A dangerous Featherstone cross was headed behind by James Riordan and from the corner, Haran rose to head towards the top corner but Nathan Hay saved the day for the Yorkshire side as he managed to nod off the line.
Five minutes later there were premature celebrations in the sparse 214 crowd as Hannah and Cropper combined sweetly and the supporting King fired beyond Sutcliffe into the opposite corner. The "goal" was ruled out as assistant Jon Abey called for offside.
Adam Sollitt, largely unemployed, kept Town level though with a superb fingertip over the bar from a Danny Davidson header two minutes before the break.
It was much the same story after the interval with Hannah not finishing off a fine flowing move involving Steve Warne, Cropper and Algar on 51 minutes. Three minutes later, Cropper struck a post with Sutcliffe nowhere before Hannah's drive was deflected wide. Algar then fired at Sutcliffe when well placed, with a Cropper header suffering a similar fate.
Substitute Danny Wood crossed for Cropper to again head at Sutcliffe before a cross frfom the opposite side by Featherstone again came to nothing as Cropper glanced his header narrowly past an upright.
Just when it looked as if Matlock would have to settle for a scoreless draw, disaster struck as for once, the hosts defended too deeply and when the ball fell to CLAYTON, the midfielder fired crisply past Sollitt to stael all three points for Ossett.
Matlock should have won comfortably but were left to rue missed opportunities. Sides like Ossett should be beaten, but if you don't take your chances, you can be bitten on the backside as the Gladiators found to their great cost.
MATLOCK TOWN: Sollitt, Brough, Featherstone, King, Haran, Lukic, Warne, Davies (Wood 70), Cropper, Hannah, Algar. Other subs: Cartwright, Pendleton, Yates, Buxton.
REFEREE: C Grundy--Sheffield. ATTENDANCE: 214 STAR MAN: Mark Haran.
