Partington unluckily clashed with a team-mate as they both challenged for the ball.
The result was out of Division II Accies’ reach early, Grouville capitalising on four set-pieces before turning round 6-0 ahead.
Accies’ best chance came from the penalty spot but Jamie Martin had his kick saved by goalkeeper Alex Buesnel.
Grouville manager Ian Horswell said: ‘We’re all gutted for Will but we’re delighted to be in the final.
Accies worked hard, they have some promising youngsters but last night they were out of their depth.
‘Our first four goals all came from set pieces and that was really pleasing.’ Accies manager Tommy Kyle said: ‘Grouville are a big side and we could not cope at free kicks.
It was a disappointing night for us but I’ve nothing but praise for my team.
I thought we passed the ball better than Grouville while they relied on long balls over the top of our defence.’ Grouville’s goals were scored by Toni Cardoso (two), Josh Collins (two), Will Partington, Murray Dron, Martyn White, Luc Le Mière and Russell Le Feuvre.
Grouville play St Paul’s in the final at Springfield on Tuesday 12 April.
Grouville: Alex Buesnel; Matt Godel (Jason Bingham, 70), Shaun Heslop, Murray Dron, Craig Northedge, Josh Collins, Russell Le Feuvre, Luc Le Mière, Martyn White (Peter Hall, 75), Toni Cardoso, Will Partington (Richard Stephens, 20).
Sporting Academics: Barry Freeman; John Irwin, Pedro Lopes, Noel Kernan, Tommy O’Hara (Jamie Savory, 45), Richard Irwin (Danny Irwin, 76), Dave Baker, Jamie Roberts, Ollie Lucas, Ben Gallichan, Jamie Martin (Michael Perreira, 55).
Officials: Nick Richardson, Ray Sutcliffe, Nigel Hammond.
