Drew Talbot's 10th goal of the season secured Chesterfield's sixth consecutive win and pushed them into the thick of automatic promotion race as Crewe were beaten 1-0.
The Spireites are now three points behind second-placed Bournemouth with a game in hand after Talbot scored the only goal of the game in the first half at Gresty Road.
Chesterfield started brightly with Barry Conlon inches away from scoring when Steve Phillips fumbled Mark Allott's shot.
But they survived a scare in the 11th minute when Byron Moore turned 20 yards out and hit a shot that bounced to safety off the underside of the bar.
John Sheridan's men recovered well and took a 27th minute when Conlon's deflected shot landed at Talbot's feet and he fired in a shot that beat the dive of Phillips by bouncing home off the desperate lunge of defender Matt Tootle.
Chesterfield were denied a second before half-time when James Bailey cleared Conlon's header off his line. Ashley Westwood had a chance to score a late equaliser but only managed to drill his shot over the bar.
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