A converted try five minutes from the final whistle by Underbank Rangers put paid to an outstanding effort by Heworth as they went down 20-16 in National Conference League division three.
The Huddersfield-based top four contenders started well to open the scoring after eight minutes at Elmpark Way, with Courtney Allette touching down following a fumble by the home defence.
Stephen Berry, the visitors’ man of the match, then crashed over for Neil Barrett to goal for a 10-0 lead.
Heworth came back strongly and on 34 minutes young substitute Conner Page narrowed the deficit with a well taken try goaled by Danny Allan.
The Villagers opened the second period in a determined fashion to pressurise the visitors line and were well rewarded when debutant Joe Deighton powered his way over the line to level the scores at 10-10 after 45 minutes.
Underbank hit back quickly with a try from Alex Chatterton which was soon cancelled out with a four pointer from full-back Christian Pollock.
Heworth edged in front for the first time on the hour mark when Allan slotted over a penalty goal.
On 70 minutes, it looked as if Allan had clinched the game when he crossed but lost the ball with assistance from a visitors hand which was not spotted by the referee.
Despite heroics in defence Heworth finally conceded the late points.
In an encouraging team effort, Deighton was named man of the match with great support from Ross and Chris Varley, David Hayes and Johnny Payne.
Meanwhile, York Acorn are fifth in division one following a 16-10 victory at Eccles & Salford.