A Louis Laing error in added time gifted bottom-of-the-pile Guiseley a unlikely 1-0 win at Victoria Park.
With Solihull Moors' match against Tranmere Rovers falling foul of the weather, Pools had the chance to increase the gap to 10 to the National League, but let the opportunity go begging as the strugglers left the Vic with all three points thanks to a last gasp Dayle Southwell winner.
On the selection front Matthew Bates stuck with 10 of the 11 who were triumphant at Maidstone - only Rhys Oates dropped out of the side, with Devante Rodney coming in.
While Pools' passing was slick in the opening 45, they lacked a killer instinct.
Only a Louis Laing header from a Blair Adams corner and a long-range Josh Hawkes effort troubled Guiseley keeper Joseph Green in the opening 45.
Needing a win, the visitors showed a bit more ambition towards the end of the opening 45, having largely frustrated their hosts.
That carried on into the second-half, and a Lewis Hawkins error opened up the best chance of the game for Southwell.
Hawkins attempt to take the ball down allowed Callum McFadzean to advance towards the Pools area, and as Scott Loach advanced he slipped the ball to Southwell, who, with the goal gaping, hammered wide. It was a real let off for Pools, who never really got going after the break.
Substitute Ryan Donaldson, back after six months out with an ankle problem which required two operations, had the chance to win it in the closing stages but he could not keep his header at the back post down.
With a point seemingly secured, an innocuous long ball forward in the 94th minute was stopped by Laing, attempting to head it away, opening up a free run at goal for Southwell, who, having missed a gilt-edged chance earlier, made no mistake.