Horsham had to win this last league game of the season with a bonus point (at least four tries) and at the same time avoid Guernsey getting a bonus losing point (win with a margin of more than seven points) to win League Two.
Otherwise Guernsey themselves would win the league and be promoted to the top league.
After only two minutes winger Rasmus Madum made it 5-0 with a strong try in the corner but Guernsey quickly responded with a try and a conversion and take the lead.
Scrum half Alex Harry grabbed Horsham a second try but back came Guernsey, again responding to lead 12-10.
Ben Murphy scored to give the young Green and Whites the lead at half time and the all important fourth try came halfway into second half when Rasmus scored his second try.
But 15 minutes still to go the nerves from the parents watching on the sidelines jangled with a successful Guernsey penalty to put them in the driving seat for promotion.
The Horsham boys though stayed focussed and two more tries from Lewis Wilson and Ollie Lewis capped the side’s best performance of the season and allowed the home faithful to finally breath
The club have thanked the coaches and parents for their support and look forward to playing Division One rugby next season.
Full squad: Callum Punter, Tom Hamblet, Sam Minto, Callum Robison, Harry Stannard, Ollie Lewis, George Carbone, Aaron Bulman, Alex Harry, Matt Allen, Lewis Wilson, James Purbrick, Ben Murphy, Rasmus Madum, Jordan Bell, John Mathews, Craig Dent, Josh Medley, Henry Purser, Piers Lydon, Harrison Gould, Louis Evans, Max Day, Sam Wheeler and Shane.