The scoreline suggested the game was a lot closer than it really was, a late goal for Rovers making it a nervier finish than it needed to be after a dominant second half performance.
The sending off of half-time substitute Emmanuel Monthe, just four minutes into the second half, gave Town a helping hand but they had been by far the better side in the first half and deservedly led through Jak McCourt’s opener.
McCourt went on to add another and Kristian Dennis made it six goals in six league games to seal the result.
Chesterfield’s pressing game almost paid off early, Louis Reed nipping in to win the ball and start an attack that ended in a Jak McCourt shot that Bradley Collins saved at his near post.
Getting tight to the visitors made it an uncomfortable first 15 minutes or so, before Mark Cooper’s side began to deal with it a little better and control possession.
But a spell of good territory was broken by an Andy Kellett turn that forced ex Spireite Jack Fitzwater into a foul to earn the game’s first yellow.
And from that free-kick Chesterfield got up the pitch, Joe Rowley drew another foul and when Kellett whipped the ball in McCourt got the faintest of glancing headers to put Town ahead.
The goal turned the momentum in the hosts’ favour, aggressive pressing causing a mistake and allowing Dennis to get in on goal, albeit forced wide and only able to earn a corner when Collins saved his effort.
Seconds later a corner routine saw the ball worked to the edge of the box where McCourt blasted just wide.
Closing down the visitors paid off again when Kellett got the better of Drissa Traore on halfway and the Forest Green man had to handle the ball to stop the attack, rightly seeing yellow.
Joe Anyon was forced into action when Reece Brown escaped the attention of Sam Hird and shot goalwards, the keeper beating it away.
It wasn’t long before Town were on the front foot again, Dennis foiled at the back post by the feet of Collins.
Rovers tried to freshen things up with a double change at half-time, but less than four minutes after coming on Emmanuel Monthe lost the ball and lunged into a tackle on Rowley to earn a straight red card.
Chesterfield wasted little time in taking advantage, attacking down the right and showing patience before the ball found McCourt and he drilled low and hard through Collins legs to double his tally.
With confidence flowing, the midfielder pulled off a trick to beat his man at the byline and his cross was turned onto the crossbar by a defender, Kellett then firing wide.
But Rovers weren’t out of it yet and when Jerome Binnom-Williams failed to control the ball when facing his own goal, Dale Bennett nipped in and found Christian Doidge in the middle to reduce the deficit.
The Spireites took the sting out of the game with a spell of controlled possession before Kellett had a golden chance to kill the game, dwelling on the ball six yards out after Collins saved from Rowley and allowing a defender to clear.
Dennis got the goal he so badly wanted with nine minutes left, Rowley jinking down the left and picking out the striker who stroked home his sixth goal in six games.
Rovers grabbed a second in stoppage time when Doidge got up to nod in a free-kick, but the full-time whistle followed soon after to set Jack Lester’s men up nicely for Saturday’s derby against Mansfield Town.
Chesterfield: Anyon, Barry, Binnom-Williams, Hird, Evatt; Weir; Rowley, Kellett (Sinnott 74), Reed, McCourt; Dennis (O’Grady 86). Not used: Parkin, Maguire, De Girolamo, Dimaio, Mitchell.
Forest Green Rovers: Collins, Bennett, Laird (Wishart 46), Iacovitti, Collins, Fitzwater; Traore (Monthe 46), Osbourne, Brown, Marsh-Brown (James 78); Doidge. Not used: Pickering, Bugiel, Randall, Roberts.
Goalscorers: McCourt 22, 54, Dennis 81; Doidge 60, 90
Yellows: Fitzwater 20, Traore 29
Red: Monthe 49
Referee: Mr Robert Jones. Assistants: Mr Paul Graham, Mr Michael D’Aguilar.
Attendance: 4306 (93 away)