Corsham had few problems stretching their unbeaten run to 12 games with a 7-1 demolition of Clyst on their own patch.
Frankie Coleman fired the visitors ahead only for Steve Norcott to level. Corsham regained the lead through Dan Beck.
Toby Colbourne single-handedly put the Southbank side out of sight with a hat-trick inside six minutes at the start of the second period John Eldred tapped in the sixth and Jack Cullis completed the rout three minutes from time.
Devizes remain in the bottom six after a 2-1 home defeat to Torrington.
Calne were held at home by fellow First Division title chasers Willand.
James Lye thumped Calne in front after 16 minutes but Steve Shore levelled after half an hour to leave the hosts in second and Willand a point behind in third.
Leaders Radstock failed to capitalise, falling to a shock 2-0 defeat at home to Minehead.
Biddestone were beaten 3-1 at Almondsbury, Joe Ochuko scoring the consolation goal.
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