The Wrens put in possibly their worst display of the season as they lost 3-0 at home to relegation rivals Parkgate, who leapfrogged above them.
Rainworth’s second defeat in five days was made worse by in-form Barton OB’s victory.
Barton, who occupy the last relegation place, are one point behind the Wrens, but have played one game more and have a vastly worse goal difference.
After a nervous opening by both sides, Parkgate took a seventh-minute lead when Lebrun Mbeka’s cross was headed in at the far post by Alex Lill.
Rainworth’s only effort of note in the first half came when Matt Sykes latched on to Curtis Birchall’s cross, but his goalbound shot was blocked by Macole Lannaman.
Declan Brewin’s attempt was then well wide.
Rainworth keeper Ben Townsend turned Lannaman’s 39th-minute effort away for a corner, but from the flag-kick Mbeka headed in.
In the 55th minute Lill’s shot was palmed away by Townsend, but it struck the covering Connor Griffin and rebounded into the net as Parkgate made it 3-0.
Rainworth hit back and in the 59th minute Ryan Herbert’s effort was tipped around the post.
Munson was also unlucky to see his 83rd-minute strike come back off the upright with keeper Ben Hunter beaten.