Petherton kicked off in freezing, howling winds and immediately put Chew Valley under pressure.
The hosts spent the early stages in their opponents’ half but Chew’s excellent defence spoilt several good chances until Petherton’s pressure finally paid off.
Sam Butler crashed over in the corner for the first try and the next followed soon after through some fine interplay between the backs and forwards, leaving a big overlap for the winger to score.
An injury to a Chew player in the second half led to the game being played with uncontested scrums as Petherton’s opponents were left without a front row replacement.
The home side dominated but Chew remained positive and scored a consolation try before the end.
Petherton’s Colts are away to Weston on Sunday.
Try scorers: Sam Butler, Sam Tozer (2), Ashly Palmer, Arran Gibbs, Toby Harris, Sam Williams, Dan Pearce.