James Clarke scored an injury-time winner as Solihull Moors twice came from behind to beat Boston.
The defender headed home Szhem Whyte-Hall's long throw in the seventh added minute after Tahvon Campbell had earlier scored his first goal since August to level things up for the second time.
Campbell made his comeback after eight months out through injury in a 10-minute substitute appearance last weekend but made much more of an impact on his return to Damson Park.
Sent on after 60 minutes, he had been on the pitch just 15 minutes when he took responsibility from the penalty spot to score the equaliser after Noah Wadsworth had brought down Fletcher Holman.
The win made Solihull mathematically safe, as there is now have a nine-point gap over 21st-placed Dagenham & Redbridge with two matches remaining, but Boston's four-point cushion is not quite enough.
Twice the visitors squandered the lead, firstly when Zak Mills scored in the second minute after Greg Sloggett had hit the post from a Bradley Nicholson throw.
Jamey Osborne volleyed home a brilliant equaliser five minutes later but, just before half-time, Connor Teale's first goal since February put Boston ahead again after Nicholson kept alive Wadsworth's free-kick.
But the hosts turned the game around in a thrilling climax.
Report supplied by PA Media.