The Blues started positively enough at Hull with Terry Devlin’s deflected shot giving them a 16th-minute lead.
However, poor defending allowed Enis Destan and Kyle Joseph to turn the game on its head, with the Tigers getting themselves in front.
Yet, in first-team half stoppage-time Devlin’s second, a head from Josh Murphy’s wonderful cross, ensured it was 2-2 going in at the break.
However, the match was settled in the hosts’ favour when Gelhardt lobbed the ball over the advancing Josef Bursik to settle it 3-2.
1. Josef Bursik - 5
Great sixth-minute block when coming out to deny Kyle Joseph but perhaps should have come off his line to deal with the right-wing corner for Hull’s second goal. Was unfortunate to be lobbed for the winner. Photo: Graham Hunt
2. Regan Poole - 7
The pick of the defence. Scrapped and battled away as ever, producing some vital blocks and clearances. Never gives up. Photo: Graham Hunt
3. Josh Knight - 6
Looked a little flat footed for the first goal when the ball was delivered from the right. Overall, though, was strong in the air, comfortable on the ball and another solid showing. Photo: Graham Hunt
4. Ibane Bowat - 5
(Replaced by Minhyeok Yang on 83 minutes) Disappointing after such an encouraging display on Wednesday. Looked vulnerable along with Williams down the Blues’ left flank in the first half and, although he improved after the break, was the weaker of the back three. Photo: Simon Roe