Jason Robertson's own goal midway through the first half was enough to hand victory to St Blazey and condemn Falmouth Town to their second home defeat on the bounce.
Robertson was the last to touch the ball after Blazey defender Dan Evans rose highest to direct a header at goal from a corner in the 28th minute.
It was tough on Town, who went on to dominate the second half. But despite creating a host of opportunities John Dent's side lacked composure in front of goal, and seldom tested Blazey keeper Ryan Walton.
In the absence of first team regulars Dan Richardson and Ed Timmons, Dent gave starts to Robertson in midfield and Joe Webb at right back.
But it was St Blazey who had the better of the opening 20 minutes, with Ashley Piggott and Tornado Bello spurning half-chances to open the scoring as Falmouth laboured on a pitch made heavy by overnight rain.
Yet despite Blazey seeing more of the ball the best chances of the first half fell to Falmouth.
Joe Cooper's header through a crowd of players forced a goalline clearance from Marcus Iles, and seconds later Andy Westgarth's back post effort drifted inches wide.
Then in the 28th minute Blazey won a corner, and a ball whipped into the six yard box saw Evans's header take a touch off Robertson before finding the back of the net.
After the break Town presed hard for an equaliser, with Harry Evans putting in a tireless shift on the right wing.
Robertson missed a good chance to head Town level from an Evans cross, and Rob Wearne lashed a shot from the edge of the box over the bar after Tom Whipp's free kick came back off the wall.
With the clock ticking down Westgarth saw another effort from a tight angle go begging.
But St Blazey always looked dangerous on the break, and last man Cooper had to be alert to cut out a pass destined for Bello late on.
In the last minute of normal time a deep cross from Evans dropped at the feet of Dominic Batchelor, but he snatched at his shot, slicing the ball well wide.
It just about summed Town's afternoon up.
Falmouth Town: D Burrows, J Webb (B Allen 83), D Batchelor, T Whipp (c), J Cooper (J Pledger 90+4), J Robertson (S Kellow 72), R Pope, H Evans, R Wearne, G Bell, A Westgarth.
St Blazey: R Walton, J Sims, M Iles, P West, D Evans, M Thackeray, T Bello, A Piggott, N Eseleyghe (J Greet 78), L Coombes, C Dan.