Devonport Services narrowly edged out Ivybridge 19-17 in the festive Oxo Cup game at Cross-in-Hand.
Both clubs usually play internal fixtures over the Christmas period but this year agreed to play each other in an adapted rules friendly.
Services had already experienced the new-look game, which does not have any scrums or mauls due to Covid-19, having overcome Plymstock Albion Oaks 17-15 the week before at Horsham Fields.
But for Ivybridge it was their first taste of the new rules rugby, which is much faster than the traditional game.
Both teams scored three tries apiece, with Rhys Williams, Charlie Crichton and Harrison Elliot crossing the whitewash for Services and Haydn Coles, Jay Geraty and Alex Gozzard touching down for Ivybridge. But two conversions by Richard West for Services proved decisive, with Matt Grieveson kicking one for the hosts.
The teams are set to meet again when the RFU cluster competitions start at the end of January.