Whilst Hereford were otherwise occupied, Kings Lynn closed the gap on them to just one point.
The mid-table visitors took a 35th minute lead through Sam Deadfield – and they held that going into the final 7 minutes of normal time as a the majority in the 581 crowd began to get frustrated.
But a Guri Demuria own goal on 83 minutes pulled the Linnets back on level terms and they produced a grandstand finale to earn a vital win, courtesy of a goal from Cameron King 2 minutes later.
The Linnets have now played two more games than Hereford.
Weymouth are third, four points behind Lynn, after winning 1-0 at the Bob Lucas Stadium against fifth-placed Slough Town.
A crowd of 822 saw Calvin Brooks` goal on the hour-mark eventually proved enough for the Terras.
Kettering Town are fourth, six points behind Lynn after a best-of-seven win against lowly Dorchester Town at Latimer Park.
A crowd of 502 witnessed a see-saw encounter that had the Magpies in front as early as the 2nd minute through Ashley Pope.
The visitors suffered a massive blow in the 38th minute when they had Ross Carmichael dismissed for two quick bookings.
Brett Solkhon eventually pulled the Poppies back on level terms a minute before the break, and the hosts took a lead into half-time as Aaron O`Connor netted his first in injury-time.
Despite being down to ten-men, the Magpies scored twice through Kyle Egan after 57 minutes and Billy Lowes 5 minutes later.
But O`Connor went on to complete his hat-trick with goals in the 75th and 87th minutes.
Royston Town and Tiverton Town are level on 64 points – seven behind the play-off places – but kept those above them on their toes after both won on Tuesday night.
The Crows, who have enjoyed a terrific first season at this level, whatever the final outcome, had top scorer Adam Marriott to thank for their 3-1 win at third-bottom St Ives Town.
He netted a hat-trick in the 24th, 49th and then in the first minute of stoppage time at the end of the game, with loanee Ben Baker replying just before the break for the Saints.
Royston moved above Tivvy into sixth after the Devonians were held to a 2-2 draw by Somerset neighbours Frome Town at Ladysmead.
Levin Landricombe gave the home side the boost of an early 4th minute lead that George Miller cancelled out just before half-time.
Jon Davies looked to have won it for Frome when he put them in front in the 87th minute.
But Tom Bath rescued Tivvy with the leveller 2 minutes later.
Hitchin Town won the mid-table battle at Stratford Town, thanks to goals from Brett Donnelly after 8 minutes and Hugo Logan after 25 minutes – Liam Francis having equalised on 12 minutes.