Marr were first to show when Olli Rossi drove over after six minutes, though Stirling came back swiftly when Logan Trotter went under the posts for a try that Jonny Hope converted.
County augmented their advantage with a Kerr Gossman touchdown, but on the stroke of half-time Mackenzie Pearce closed the gap to 12-10. After the break, Stirling won a seven-point penalty try, only to see Marr respond quickly when Tom Steven scampered in, Dougie Steele adding the extras.
Marr then stunned their hosts by regaining the lead when Scott Bickerstaff grabbed a try, Steele again converting, but the match see-sawed once more when Gossman secured his second touchdown, Hope putting Stirling ahead with the extras.
Matt Emmison then put the match beyond Marr with a score that Hope goalled, and Kennedy iced the cake with a try, Hope again on target. Pearce reduced the deficit at the death but it was too little, too late.