IAN Herring's second-half penalty was enough to beat King's Lynn and extend Chippenham's leadership of the Premier Division.
The former Swindon Town youngster, pictured, coolly dispatched the spot-kick after all hell broke loose on the hour.
Sam Allison was running away from goal when he was brought down by Ludovic Quistin.
Referee Kevin Pike waved play on but his assistant flagged for a spot-kick.
A mass brawl broke out as the decision was contested and Gary Thorne was one of three players booked as punches were thrown.
When the dust settled, the referee reversed his decision and Herring in the absence of regular penalty taker Scott Walker rolled in the decisive goal.
It was hard on the visitors who had dominated for long spells.
Lynn bossed the first half, though Dave Gilroy squandered arguably the best opening for Chippenham, missing a virtual open goal.
After the Bluebirds had gone a goal up, King's Lynn had a penalty appeal of their own turned down when Sam McMahon's shot struck the hand of Matthew McEntegart.
McMahon was given his marching orders with 20 minutes left after picking up a second booking but the 10 men still should have pinched a point Chris Bacon dragging a fine chance wide at the death.
Inactive Cirencester slipped to a season's low ninth place as results elsewhere went against them.
Chesham and Tiverton both won to climb above the Centurions in the race for a play-off place.
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