Borough battled hard and created a number of chances as Theo Lewis had a goal disallowed in the 81st minute, after the referee blew for a foul on Truro’s keeper.
But Truro scored in the final seconds of the match, as a long free kick was not cleared away, leading to a heartbreaking defeat in the 95th minute.
Moneyfields travelled to Paulton Rovers, but an early goal was cancelled out when Paulton replied with three goals of their own, before Matthew Brown scored for the game to end in a 3-2 defeat.
In the Wessex Premier, Steve Ramsay scored twice for AFC Portchester against Hythe and Dibden, helping his side to a 3-2 win.
Fareham Town were beaten 3-2 away from home against East Cowes Victoria Athletic.
Meanwhile Bognor had a day to forget away to East Thurrock United, losing 3-0.