Scarborough Pirates under-15s claimed a huge scalp on their travels by beating league leaders Wibsey 18-12.
Having lost only one game all season, Wisbey were strong favourites for the clash.
They mounted early pressure that led to a 4-0 lead.
The introduction of Zak Kirk and Dan Wallace made an immediate impact, with Kirk notching his first try of the game with a thunderous run through the home defence, Jordan Pickard adding the extras for a 6-4 lead.
Kirk then doubled his tally with a carbon copy drive from close range, the conversion making it 12-4.
From the restart the Pirates made good ground, and on the last tackle Pickard floated a great chip into space that was regathered and pushed out to Dan Wallace, who skilfully sidestepped his marker to score under the posts and give the Pirates an 18-4 half-time lead.
Unable to press home their advantage, the Pirates began to make errors and the home side came back into it.
Wibsey scored two tries to get them within touching distance, but huge defensive efforts ,in particular from Ben McCue, Liam Atkinson-Smith and James Clifford, kept them at bay for a memorable win, their third on the bounce.