Watford Water Polo Under-17s progressed into the ASA NAG Championship finals as group winners last weekend.
Two wins would secure progression as group winners and Watford got off to the ideal start against City of Sheffield in their first game.
A hat-trick from Hamish Hudson and a Paul Botje brace had Watford 5-0 up at the end of the first quarter.
Five further goals from Hudson (two), Cami Baker, Adam Kohler and Jonny Walker in the second period put Watford 10-0 up.
Sheffield conceded another eight times, with Hudson adding two more, Sam Carling getting a brace and further goals from Alex Norcliffe, Botje and Kavi Shah.
Watford’s second group game saw them face holders City of Manchester to decide who would progress as group winners.
Botje opened the scoring for Watford after just 43 seconds but Manchester quickly levelled.
In a frenetic first half, Hudson restored Watford’s lead before Botje added a third.
With only seconds of the first quarter remaining, Manchester pulled one back to make it 3-2 to Watford.
Two quick-fire goals at the start of the second period put Manchester ahead for the first time, but Botje completed his hat-trick to make it 4-4 at half-time.
Manchester opened up a 6-4 lead in the second half, but Watford were not to be denied.
Carling grabbed one, before a brace from Hudson and another from Botje turned the match on its head, Watford heading into the final quarter 8-6 up.
Watford moved 10-8 ahead in the final quarter, with the goals coming from Hudson and Carling.
Manchester did pull another back, but Watford held firm to reach the final.
Croydon await Watford in the semi-finals, with Manchester taking on Invicta in the other semi.