Horndean came from a set down to notch up a startling 3-2 win away to Bristol 1 and seal a spot in the NVL promotion play-offs.
The Deans went into this national league division two south encounter with many key players missing.
Their recent loss to Solent 2 had also slightly opened the door for Bristol to snatch second spot had Horndean failed to honour this fixture.
But the Deans managed to make the long trip to Abbeywood Community College with only six players – including two inexperienced youngsters.
Despite their troubles, Horndean had to remain unfazed by the fire power on the other side of the net.
They opted to play their upcoming players Jack Whitlock and Matthew Jackson through the middle, leaving the experienced trio of Nasser Ssemuwemba, Maciej Kubis and Damian Roberts as outside hitters.
The move to tinker with the starting positions worked, as Horndean led 8-7 by the first technical time out.
Although the lead continued to change hands, it was the Deans who once again reached the second time out ahead 16-14.
However, the home team later recovered to clinch the set 25-23.
Buoyed by their surprise performance in the opening set, the Deans exhibited a dominating display in both the second and third sets which they convincingly won 25-18 and 25-19 respectively.
But Bristol bounced back to level terms with a vengeance, after whipping the visitors 25-13 to push the match to a pulsating decider.
A tense fifth set started closely as both teams matched each other point for point.
However, it was Horndean who broke away to assume a 15-12 match victory – with a combination of clever off-speed play, well-placed spikes and tough serves.
The Deans’ player-coach Ssemuwemba paid tribute to his battling team’s stunning victory.
He said: ‘This is arguably one of the best wins of the season.
‘I want to thank the magnificent six who travelled to Bristol and got us this unbelievable result. All I can say to Jack and Matthew, is that the sky is the limit for you guys and you are without doubt the future stars of the team.
‘The chance to be involved in the play-offs will not have been possible, without your splendid performance.’
The Deans completed this season’s league term with 46 points in the bag, four behind eventual winners Wessex BU.
They will now face Birmingham and Nottingham Rockets 1 in the NVL promotion play-offs at the national volleyball centre, Kettering, on Sunday, May 11.