The Spireites closed the gap to Woking with a hard-fought 1-0 victory over Dagenham & Redbridge at the Chigwell Construction Stadium.
Liam Mandeville’s smart header in the 71st minute secured a sixth successive away game without defeat.
Paul Cook made three changes after Good Friday’s 3-1 home defeat to York City as Ryheem Sheckleford, Darren Oldaker and Joe Quigley came into the starting XI.
Chesterfield started brightly. Sheckleford made an early break down the right side and sent in a low cross that was parried out by Elliot Justham – Quigley missed out on the rebound.
Ollie Banks also tried his luck for an early opener for the away side; his long-range effort rolled wide of the mark.
The game was controlled well by the Blues, but chances were very few and far between.
Ryan Colclough almost opened the scoring on the half hour mark. His low drive from the edge of the area was tipped around the post by Justham.
Oldaker lifted a ball into Quigley soon after. The striker controlled it well with his chest before rattling the crossbar with a stunning volley.
Ash Palmer managed to keep the scores level going into the break as he provided a last-stitch tackle to deny Mo Sagaf.
The opening exchanges of the second half saw both sides cancel each other out as efforts on goal became hard to come by.
Laurence Maguire almost marked his 150th league appearance for the club with a goal as he nodded Mandeville’s corner the wrong side of the post.
The goal came with less than 20 minutes to go. Banks floated a ball to the back post, where Mandeville was on hand to head back over Justham for his eighth goal of the season.
Chesterfield came close to securing the game with style as Jesurun Uchegbulam was denied by Justham and Oldaker clipped the post with an effort.
With time almost up, Dagenham threw everything forward to try and get an equaliser. Inih Effiong was denied by Ross Fitzsimons with a shot.
The resulting corner caused chaos in the area with the ball eventually cleared away to signal the full time whistle.
The win means that the Spireites need just one point in their last four games to secure play-off football for a third consecutive season.
Chesterfield: Fitzsimons, Sheckleford (Uchegbulam 46), Palmer, Grimes ©, Maguire, Jones, Banks, Mandeville, Oldaker, Colclough (Asante 82), Quigley (Dallas 86).
Unused Substitutes: Horton, Williams.