Jersey's Kieran Hardy scored the winning try in the dying minutes, following up his own charge-down to send the home crowd into raptures.
The replacement scrum-half's decisive intervention earned four valuable points for his side against opponents who began the day level with the Reds on 29 points and six wins.
Nick Selway's 13th try of the season from a powerful driving maul gave the home side an early lead after a penalty was kicked to the corner. Richmond's Rob Kirby's missed one penalty chance to reduce the arrears but then slotted his next attempt after Ross Grimstone charged down a 22 drop-out by the Reds.
When Jake Armstrong was yellow-carded for taking down a Richmond maul, the Reds were forced to dig deep in defence, but managed to survive until the break without conceding any further points.
The error count by both teams increased in the second half with a large number of handling errors in greasy conditions and inaccurate kicking, especially by Jersey. The home side maintained a territorial advantage, but on their two forays into the opposition's half, Richmond won penalties which Kirby slotted to put his side in front.
The Reds finally managed to increase the pressure in the closing stages; Josh Hodson crossed in the corner but play was called back for a forward pass, but soon afterwards Hardy flung himself at an attempted clearance by Kirby and was first to react and pounce on the loose ball.
Head Coach Harvey Biljon was both relieved and frustrated after the game.
"We will take the win and I think had a bit of luck on our side at the end, but I was disappointed with our inaccuracy and inability to control the pitch - there were a large number of opportunities we couldn't take.
"There are a lot of areas we'll need to work on, but I was pleased to only concede nine points - our defensive record is excellent and we'll need that given that we face Bedford, Ealing and Bristol in our next three games."
Richmond DoR Steve Hill was disappointed his players couldn't hold on to win.
"I think we did enough to win the game - we knew Jersey had a strong pack and the conditions probably favoured them, but I thought our pack really fronted up and we put ourselves in a position to win the game," he said.
"I was proud of the effort and the discipline of the players - we knew we'd be punished if we conceded penalties. Coming away with a point is our best result here in recent years."
JERSEY REDS: Van Breda (c); Worrall, Best, Ma'afu, Hodson; Cope, Dudley (Hardy 55); Woolmore (c) (Godfrey 58), Selway (Macfarlane 55), Armstrong (YC 27) (Atalifo 62), Sexton, Voss (Quarrie 79), Bartle, Joyce, Argyle. Not used: Kolo'ofa'i, Bryant.
RICHMOND: Kirby; Woodward, Mitchell (c), McLean, Simpson-Hefft; Damant, Gibbs; Cunnew, Grimstone (Phipps 70), Tarrant (Trenier 67), Davies, Crawford (Humfrey 79), Parker (Scott 55), Liston, Edwards. Not used: Goodrick-Clarke, Adamson, Swan.
REFEREE: Tim Wigglesworth. Assistants: Clare Daniels, Ian Bibey
ATTENDANCE: 1,184
Half Time: 5-3
Man-of-the-match (as chosen by Match Sponsor Brooks Macdonald): Kieran Hardy (Jersey)
Scorers
Jersey Reds
Tries: Selway 6, Hardy 74
Richmond
Penalties: Kirby 13, 53, 66
