The Spireites' win came on top of the postponement of the game between second and third-placed sides Rotherham and Shrewsbury.
Stephen Hunt's shot was tipped over for the hosts before Chesterfield took the lead after quarter of an hour through Craig Davies.
However, Chesterfield did double their lead six minutes from time when Dean Holden headed home.
Wycombe had the chance to move into second place when they hosted Accrington Stanley, but they failed to take advantage as they went down to a 2-1 defeat.
Joe Jacobson put the visitors ahead two minutes from half-time but the Chairboys levelled through Scott Rendell's close-range shot seven minutes after the break.
However, Accrington's Phil Edwards headed home in the 82nd minute for a shock victory.
Gillingham and Bury, seventh and sixth at the start of play, shared a 1-1 draw.
Curtis Weston drove the ball home for the Gills before Ryan Lowe levelled from close range.
Asa Hall scored twice as Oxford won 3-0 at Morecambe to go level on points with Gillingham.
Hall scored in the 30th and 66th minutes with Paul McLaren also on target with a 25-yard shot.
The hosts missed a penalty with 20 minutes left when Laurence Wilson's shot was parried by Ryan Clarke.
A late goal by Scott Laird guided Stevenage to a 1-0 win at Crewe.
Torquay and Southend drew 1-1. Billy Kee put the hosts ahead in the 73rd minute before the Shrimpers levelled through Billy Corr nine minutes from time.
Northampton and Aldershot finished with the same scoreline, Ben Tozer giving the Cobblers the lead before Peter Vincenti levelled.
Joe Devera scored an injury-time goal as second-bottom Barnet drew 1-1 at Cheltenham.
Wesley Thomas had put the Robins ahead with half an hour left.
Hereford and Burton drew 0-0 while Macclesfield won 4-1 at Stockport.