Latics fell to defeat in front of a packed Boundary Park, with Reiss McNally winning it for the visitors.
Kidderminster started brightly, and got what they deserved when Alex Penny’s deflected shot snook in at the near post.
Oldham came out with attacking intent in the second half, going ahead via Nathan Sheron, but momentum did not fall Latics’ way, and McNally’s header won it for the Harriers.
Kiddy dominated the opening plays of the game, having a number of good chances, which Latics had to defend well.
Sam Bellis' shot was destined for the goal, but a deflection from an Athletic man pushed it wide of the goal.
Hobson was called into action as well, making a vital interception and then clearance, as the visitors looked to square it.
Eventually, the goal came, Penny finding space outside the box, taking aim on goal, with it taking a deflection before beating Hudson.
Latics had a penalty appeal waved away when Hammond, who’d done brilliantly to advance into the box, went down inside the area.
Ashley Hemmings looked to double his side’s lead just before half-time, but his long-range effort was always rising.
Micky injected some attacking impetus into his side after the break, and soon saw it come to fruition, when Mike Fondop moved into the box, switching possession to Sheron who slotted home from a tight angle.
Oldham had a great chance to complete the turnaround moments later, Sheron pulled off an overhead kick to move the ball forward for Lundstram, who hit it first time, on the half-volley, but could only aim it straight at Dibble.
In the next play, Hemmings swung in a corner, finding McNally who headed home with precision, giving Harriers the lead once more.
Micky Mellon responded by bringing on Devarn Green in place of Oli Hammond, before bringing on Andrew Dallas for Fondop.
Lundstram had a chance again with 15 minutes to go, sticking his leg out as the ball was headed across the face of goal, but his effort was blocked on the line.
Latics spent the last third of the game with most of the ball, trying and trying to find an opening, but Kidderminster held strong, and just wouldn’t let Latics through.
Oldham had a few free-kicks near the end of the game, Dan Gardner, who’d come on for Sheron with six to go, fired them in, with one header going just over the crossbar.
Oldham: Hudson, Kitching, Hogan, Hobson, Lundstram, Fondop, Sheron, Raglan, Garner, Hammond, Conlon.
Subs not used: Norman, McGahey
Kidderminster: Dibble, Penny, Richards, Pearce, McNally, Morgan-Smith, Hemmings, Lambert (Omotayo, 77’), Brown, Bellis, Byrne (Griffiths, 45’)
Subs not used: Oxlade-Chamberlain, Hesketh, Emmanuel-Thomas.
Attendance: 11,881
Referee: Richard Eley