With three of this season's skippers unavailable, the Shrimpers' classy full-back Reece Harte took the armband for this match in Norwich.
Harwich made a good start, attacking from the kick-off, and took the lead after 10 minutes with a super strike from Joe Knight, who from wide on the left-hand flank, angled his shot into the far corner of the net.
On their artificial surface, Dussindale came back into the match, causing Harwich problems in midfield and Shrimpers keeper Brad Cook did well to tip a dipping ball over the crossbar.
With half time approaching, Harwich had a good opportunity when Louie Bloom's excellent cross played Alfie Canning in but his effort was blocked.
Dussy had been in contention in the half and just before the break mounted a dangerous attack with Shrimpers defender Dan Keeble managing to toe away a cross.
Early in the second half, Dussindale goalkeeper Kingsley Barnes was in action and Knight had a goalbound header well stopped.
With 55 minutes played, Harwich increased their lead with a route-one move when central defender Jack Wood picked out Knight with a long pass and he beat Barnes with a clinical finish.
Harwich had tightened up in midfield and were now controlling proceedings, although when Dussy broke away Cook did have to make his second excellent save of the match.
As ever, Bloom's work-rate had been excellent, and when his shot came off a defender, man-of-the-match Knight (pictured) pounced to complete his well taken hat-trick.
Manager Matt Carmichael and his assistants have assembled such a strong squad that he was able to bring on his 5 substitutes that included striker Danny Garrad, who slotted in the 4th goal after Tyler Sullivan had teed up the opening.
Harwich team: Brad Cook, Keelan Milburn, Dan Keeble, Jack Wood, Reece Harte (C), Tyler Sullivan, Alfie Eldridge, Liam Riley, Alfie Canning, Louie Bloom and Joe Knight. Substitutes: Liam White, Danny Garrad, Greg Rodger, Ewan Livingston and Harry Tuck (all used)