The former City of Plymouth under-17 athlete, who now competes in Newquay & Par colours, edged out South West Road Runners’ Jack Turner by five seconds.
Marriott clocked a new personal best gun time of 35 minutes and 10 seconds (35:09 chip time), with Turner clocking 35:15 minutes.
Junior athlete Marriott was nearly three minutes quicker than he was over the same Tamar Bridge course last year on his 10k debut.
Tavistock AC’s Hannah Smith was a dominant winner of the women’s race, taking victory by nearly two minutes. She clocked 38:59 minutes.
Sophie Court (F40), Caroline Nickson (F45), Jacqueline Woodward (F50), Mandy Watts (F55), Catherine Shortman (F60), Aileen Barwell (F65) and Janet Watson (F70) were all female age category winners.
The race started at Marine Academy Plymouth and took runners across the Tamar Bridge twice before finishing at Kawasaki Precision Machinery.
Full results can be found HERE.
Meanwhile, Lloyd Milbourn took victory in the Eden Half Marathon on Sunday in 1:22.53, with Storm Plymouth’s Daniel Westlake finishing as sixth man.
Storm’s Lauren Knox came second woman in 1:30.38, while Tamar Trotters’ Alison Caldwell was first F45 and Erme Valley Harriers’ Alison Engledew was second F60.
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