The Pilgrims had trailed 3-1 with only 15 minutes to go - the County goals being shared by two Boston old boys in the guise of Jason Lee and Alan White.
But United valiantly fought back to net a share of the spoils in their relegation struggle.
Neither side really got into an attacking groove in the opening exchanges, but Boston's position wasn't helped by a tenth minute injury to skipper Paul Ellender.
The Pilgrims, already reduced to 14 fit players with only three subs on the bench, pitched 17-year-old Jamie Stevens into the rearguard as a replacement.
However, Boston remained positive and went close in the 14th minute when Francis Green flicked a header wide from Dany N'Guessan's cross.
The home side, though, broke the deadlock on 24 minutes. A Jamie Clarke free kick was curled into the County area and Stevens rose to send a header beyond Kevin Pilkington.
But the visitors levelled in the 28th minute when Lee profited from a Junior Mendes lay-back and sent a bouncing left-foot 18-yard shot past Andy Marriott.
County, buoyed by their equaliser, pressed forward more regularly with Mendes' low shot forcing Marriott into saving action and then Ian Ross cutting in from the right only to blaze high and wide.
The visitors went ahead two minutes after the break when a deep free-kick by Gary Silk was only partially cleared by the home defence and White swivelled to crash home a rising 12-yard angled drive.
Sixty seconds later the visitors made it 3-1 when Stevens misguided a header straight to Lee who buried a 15-yard shot low into the net.
Boston tried to find a response and exerted a degree of pressure without being able to unduly trouble Pilkington apart from a 58 minute drive by N'Guessan which the County keeper held securely.
Back at the other end County went close again when Mendes delivered a raking shot from the left and Marriott went full stretch to push the ball aside.
Boston cut the deficit in the 75th minute when Anthony Elding got on the end of an N'Guessan cross and forced the ball over Pilkington from eight yards.
And the Pilgrims drew level on 86 minutes when Clarke crossed from the right and Green stabbed in from close range.