Martin was a surprise entry on his BSA machine as he turned up in the paddock at the weekend with his bike in the back of a van, much to the delight of his many fans.
The English rider won his class at the Tandragee 100 in May after missing the Cookstown 100 and Martin was again in fine form around the 2.9-mile Skerries course.
However, he was pushed all the way for his victory by Richard Ford, who led the race on the opening few laps before Martin forged ahead.
Lincolnshire's Guy Martin won the Senior Classic race after a close battle with Richard Ford at the Skerries 100.
The 37-year-old was unable to pull away though and Ford chased him all the way to the finish, with Martin narrowly holding on by just 0.067 seconds after six laps. Ben Rea finished third ahead of Barry Davidson.
Martin’s select appearances at the Irish road races this year are his first since 2017, when he competed at Cookstown and Tandragee as part of his preparations for his high-profile Isle of Man TT comeback with the Honda Racing team.
He crashed at the TT in the Superbike race at Doran’s Bend and the team later withdrew from the Senior race. Martin’s short-lived association with Honda ended soon afterwards and his road racing exploits have since been limited to the Classic scene.