Captain Jacob Kern put in an MVP performance and then won five of the last six points for his team as they edged home by two points in the tiebreaker.
He said: “It was a really fun game to play, glad we could end the season on a high note.
“We struggled in the first half of the match but found a way to stick with it and get the job done.
“Happy for the graduating guys to get one last victory to cap a career off!”
'Immensely proud'
The dramatic clash and victory were bittersweet for the Rebels as it marked the last time the current squad will play together.
Alex Porter, Head of volleyball, said: “What a way to end the season! I’m over the moon for the team, coaching and support staff.
“After narrowly missing out 3:2 in our previous two Super League encounters, I’m immensely proud of the lessons the team learnt to flip the result, especially after being 2:0 down in the game.
“After winning BUCS gold, the Super League regular season title, silver at the Final 4 and now the National Cup, this is undisputedly the most successful team in Essex Rebels’ history.”