After William Creighton crashed out of contention on Saturday’s opening stage, Pellier was gifted a commanding 4min15sec lead, but head gasket issues caused the Frenchman to cede handfuls of time to his pursuers.
With no answer to his issues beneath the bonnet, the defending FIA Junior ERC champion then found himself forced out completely on the penultimate stage.
That looked set to promote closest rival Tom Rensonnet to the top spot, but the Belgian was battling engine dramas of his own, elevating Kelly from third to first in one fell swoop. The Irishman then managed the gap over the final stage to pip Rensonnet to glory by 30.8sec.
Roberto Blach rounded out the rostrum in a distant third, 36min25.4sec adrift of Rensonnet, with Hamza Anwar, the delayed Creighton and Filip Kohn completing the top six.