Chasetown made a positive start on a tricky surface but a Liam Holt effort way over the bar was their sole attempt in an otherwise one-sided game.
Ryan Wynter had the ball in the net but that was quickly ruled out for an offside against Mitch Piggon.
Gresley lost their goalkeeper Robert Peet to a painful leg injury that stopped the game for eight minutes until he was stretchered off.
Gresley took a shock lead when Josh Ruff conceded a penalty and Thomas Manship fired the kick in off the post with Curtis Pond diving the right way.
Jack Langston was a fingertip away from equalising with a free kick from the edge of the box that makeshift keeper Matthew Melbourne was equal to with a spectacular save.
# | Team | Pl | Pts |
15. | Sheffield FC | 42 | 48 |
16. | Stamford | 42 | 48 |
17. | Chasetown | 42 | 47 |
18. | Gresley FC | 42 | 45 |
19. | Carlton Town | 42 | 42 |
20. | Loughborough Dynamo | 42 | 34 |
21. | Rugby Town | 42 | 30 |