Guernsey have gone two points clear at the top of London One South after a 53-10 win over Dover at Footes Lane.
The bonus-point win, coupled with Chichester's 34-12 loss to Old Elthamians, means Guernsey take the lead with four matches left to play.
The island side face Chichester next week in a game that could go a long way to sealing the title's destination.
"If we lose any games we're going to see ourselves out of first spot," coach Jordan Reynolds told BBC Guernsey.
"We've got four games to go and we need to win every one and pick up bonus points if we can," he added.