The Crusaders started the evening just three points above the drop zone, while the Saints travelled occupying a play-off place, but embroiled in a really tight battle for a top seven spot.
The visitors, who were beaten at home by fellow contenders Truro City, got off to a good start when they took an early 6th minute from the penalty spot converted by David Noble after a handball decision.
Hungerford though took only 9 minutes to pull back on level terms in rather fortunate circumstances when a cross from Louis Soares sailed over the head of Saints` keeper Dean Snedker and into the net.
The remainder of the first half was fairly end-to-end and even.
But 11 minutes into the second period, the Crusaders went in front when Soares got hold of the ball 30 yards from goal and burst through and fire past Snedker.
Then on the hour-mark, Hungerford made it 3-1 and virtually game over when they were awarded a spot-kick for a foul by Snedker on Nick Bignall and Soares completed his hat-trick from the resulting spot-kick.