Trinity have been relegated from Jersey's top flight after a 12-year stay in the Premiership.
They lost 2-0 to fellow strugglers St Ouen, who ensured their own safety with the victory.
Marco Vieira netted the opener after half-time, with Neil Langdon heading in the second.
Grouville beat Jersey Wanderers 2-0 in Saturday's only other Jersey Premiership fixture.
Scott Walsh and Luc Le Miere getting the parish side's goals.