Jarvis has been improving every month since the opening run in October.
He had claimed a seventh and two fourth places before finishing second in February.
However, he finally secured top spot in March’s run with personal best time of nine minutes and 50 seconds for the course around Central Park.
That was 10 seconds faster than he had run the previous month and a minute quicker than his opening race in October.
Erme Valley Harriers’ Nathan Brown, who had won February’s run, had to settle for second on Wednesday in a time of 10.12 seconds.
Plymouth Harriers’ Chris Aldridge claimed third for a second month running in 10.15.
Alridge was followed home by his Harriers’ team-mates Steve Hill (fourth, 10.37) and Alex Peyton-Jones (fifth, 10.41).
Fellow Plymouth Harriers Ami Yetton and Jane Allison were the first two female runners home on Wednesday. Yetton produced a good performance to finish seventh overall in a time of 11.08, with Allison clocking 12.11.
Full results can be found HERE