Gloucestershire Warriors marked their 100th competitive game with a shock 25-24 win over Illingworth in the preliminary round of the Challenge Cup.
The match was heading for a draw until scrum-half Danny Burke landed a drop goal with just 30 seconds remaining.
The Harpbury College student also scored a try and kicked four goals.
Head coach Dan Garbutt, in what should have been his last game in charge of the Rugby League Conference side, also made an appearance from the bench.
"We won the South West Division last year and reached the Grand Final but to beat a Pennine League side in their own backyard has to be the club's best ever result," said Warriors spokesman Chris Wilson.
The Warriors, a part-time outfit based in Churchdown, trailed 20-12 at one stage before mounting their fightback.
Also touching down for the visitors were prop Karl Kocerahan and hooker Andy Bird (2).
The game should have marked Garbutt's final one as head coach following his move to Super League side Harlequins but he will now stay on for the first round, the draw for which is made on 20 January.
The Warriors are joined in round one by Barrow Island, who beat Keith Senior's Huddersfield Sharks side 44-10.