The fifth-placed Martyrs took an early seventh minute lead through Ryan Prosser and the same player doubled their advantage on the half-hour mark.
The old adage of 2-0 being a dangerous lead proved right again as Chippenham reduced the deficit immediately after the break through Andy Sandell, who matched Prosser by adding a second to equalise, this time from the penalty spot, 13 minutes from time.
Frome Town moved to within four points of Merthyr after increasing Hayes & Yeading United`s fears of back-to-back relegations.
The Somerset visitors were two-up inside 20 minutes, thanks to Jake Jackson and Clayton Green. Mitchell Weiss pulled the hosts back into the game after 34 minutes but a second for Jackson after 69 minutes sealed Frome`s win and leaves Hayes & Yeading three points behind the safety-mark.
St Ives Town inched further towards mid-table after a 1-1 draw against the team immediately above them and level on points with, Dorchester Town.
A Liam McDevitt own goal broke the deadlock to give the Magpies a 55th minute lead. But five minutes from time, Josh Dawkin made the long midweek trek back to Cambridgeshire a little happier.
King`s Lynn Town also had a lengthy midweek trip to play Basingstoke Town at the Camrose and returned home with all three points from a 2-1 win in which Dan Quigley gave the visitors a 23rd minute lead.
Lee Stevenson doubled the Linnets` advantage just before the break, and they held firm, despite Aaron Jarvis` 69th minute response.
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