There was a bumper crowd at Coggeshall Town's West Street stadium to witness this all-Essex Thurlow Nunn League Division One North play-off final.
The strong, swirling wind and hard surface made things tricky for the players but added excitement for the supporters basking in the lovely sunshine.
Harwich's first scoring opportunity came in the 13th minute with Alfie Canning crossing for Alfie Eldridge to head inches wide of the far post.
The Shrimpers' good start continued with Reece Harte firing in a dangerous free-kick which former Harwich goalkeeper Sam Felgate did well to punch over the crossbar.
With Tyler Sullivan and Eldridge in fine form in midfield, Harwich were quicker onto the ball and midway through the half took the lead when Canning provided the assist for Luke Mayhew to convert with a well-placed finish.
Harwich had been on top but with half time approaching, the match swung dramatically in Pegasus' favour. Initially they won a corner kick from which their captain, Zack Smith-Walter, lofted the ball into the swirling wind perfectly to the far post for Tom Lewis to head the equaliser. Minutes later Lewis snatched the lead for Pegasus with a stunning 30-yard bolt-from-the-blue that eluded Shrimpers goalkeeper Brad Cook's desperate attempt to save.
Pegasus came out for the second half buoyed by their success and Harwich had to fight hard to come back into the game.
Harwich found Pegasus strong in defence and they successfully repelled two free kicks which the Shrimpers won on the edge of the penalty area.
Midway through the half, Harwich manager Matt Carmichael decided to use his substitutes in an effort to make a breakthrough and this produced success with Joe Knight heading the ball down for sub Luke Spurling to level the scores with a neat finish.
Pegasus attacked and Harwich were forced to make a goal-line clearance. Another tense moment for the Shrimpers supporters came when Pegasus had the ball in the net but the assistant referee had his flag raised for a foul on Cook.
With the result on a knife-edge and both teams looking for a winner, Spurling was providing an added threat in the Harwich attack and from his good work Louie Bloom was just unable to get enough power in his header to test Felgate. At the other end, when Pegasus threatened, Cook did well to powerfully punch the ball to safety.
So, the result was to be decided by a tense penalty shoot-out. Four perfect spot kicks from both teams followed (Liam White, Spurling, Mayhew and Bloom for Harwich). Then, Harwich with the advantage of taking first, saw Knight clinically despatch their 5th spot kick and Pegasus had the heartbreak of theirs missing the target.
It is so hard in words to do this super match justice and also to describe the joyful Harwich celebrations in style with their supporters that followed their victory.
The Shrimpers will now move up to Step 5 of the Non-League Pyramid in 2025/26.
They will either play in the Essex Senior League, alongside teams such as Little Oakley, or the Premier Division of the Thurlow Nunn League. The FA's decision is expected in mid-May.
Another bonus of returning to the higher level is that Harwich are now eligible to compete in the FA Cup again - their opening tie in August will be their first in the competition for six years.
Harwich team: Brad Cook, Keelan Milburn, Reece Harte, Jack Wood, Dan Keeble, Tyler Sullivan, Alfie Eldridge, Alfie Canning, Luke Mayhew, Joe Knight, Louie Bloom. Subs: Alfie Smith, Gareth Heath, Liam White, Luke Spurling (all used) & Oakley McNair (not used).