Goals from midfielder Joshua Scully and striker Bradley Bowland gave Chesterfield a well deserved victory over local rivals Rotherham United.
It was the Spireites first win in 2013, ending a run of seven games without victory. The visitors could have added more goals on the day with Bowland hitting the woodwork on two occasions.
Manager Dave Bentley made three changes following the defeat to Burton Albion last week with midfielder Oliver Brock replacing the injured Alex Hewitt, Ben Partridge coming in for Cormac Noel on the left and goalkeeper Cameron Mason returned in goal in place Jason Alexander.
Chesterfield's first chance of the game fell to striker Joe Mathers. He did well to create some space for himself outside the box but dragged his effort wide of the post.
In the early exchanges it was Bentley's side who took the initiative and were inches away from taking the lead in the 18th minute. Scully's free-kick found Bowland who flicked the ball over the Rotherham 'keeper Charlie Bryan but the ball bounced off the crossbar twice and United cleared the danger.
The Yorkshire side were given no time to settle on the ball as Bentley's side hassled and pressed them to good effect with Scully and Brock dictating the pace of the game.
Despite a bobbly pitch and a light shower of snow, Chesterfield coped with the tricky conditions and used possession well on the field. Midfielder Mark Fereday's pace was causing United's defence all sorts of problems as the visitors continued to dominate the first-half.
An excellent counter attack in the 30th minute gave Chesterfield a deserved lead with a superb team goal. Scully picked up the ball in his own half and found Bowland who sprayed the ball to the right to Fereday. He did well to beat defender Laurence McKay and cut the ball back to Scully who had continued an outstanding run into the box and slotted home with a neat finish.
United slowly started to creep back into the game just before half-time and created a few opportunities. Midfielder Nicky Walker's long- range effort sailed over the bar, and a minute later Mason made a great reaction save following a dangerous corner from Phil Woods which took a wicked deflection.
The Spireites defence had to stand firm as the Millers mounted some late pressure but they held on to take a narrow lead into the break. Despite an impressive performance Bentley was dealt a blow as Fererday was forced off through injury and replaced by striker Fabian Johnson.
After a dominant first 45 minutes, Chesterfield were put under early pressure in the second-half as the Millers took the game to Chesterfield. They showed great desire and urgency to force their way back into the contest. McKay was causing problems down the left but despite a pin-point cross to Walker, his header was straight at Mason.
Midfielder James Cadman was the latest Millers player to see an effort go over the bar as Bentley's boys were struggling to cope with the Millers, who edged closer to an equaliser.
On the hour-mark Mason prevented a certain goal. Midfielder John Travis managed to bring the ball down well in the six-yard box following a cross from McKay. He swivelled and unleashed a fierce effort which was heading towards the bottom corner of the net before a full stretched Mason clawed it away and the danger was cleared.
As the pressure soared the Spireites always looked a threat on the counter. It was Scully again who was pulling the strings in midfield and he tested Byran after playing a neat one-two with Partridge on the edge of the box, but his shot was spilled and nobody was there to pounce on the rebound.
Defender Tim Whittaker should have doubled the lead for the North Derbyshire side after a corner from Scully found him unmarked in the box, but his header whistled agonisingly past the post.
The Spireites did manage to double their lead with an incisive break away with only fifteen minutes remaining.
Defender Jamie McNicholas picked out Mathers in plenty of room and after he had burst away from United's centre-backs, he switched the ball to the opposite flank to the unmarked Scully. He lofted the ball up in the air and the ball bounced back off the crossbar and the instinctive Bowland followed up to all but sealed the three points.
Bentley brought on Under 15 striker Curtis Morrison for Brock as Johnson moved to the right side of midfield and Bowland dropped into the middle in order to the game out and claim a precious three points.
The Spireites dug in deep in the final ten minutes and were excellent in defence, with striker Luke Beedham's header the closest the Millers came to getting into the contest. Bentley's side might have added to their lead after Johnson and Morrison had half chances but claimed a priceless win on a bitterly cold day in Rotherham.
Bentley couldn't hide his delight following his side's performance.
He said: " I thought we were excellent today. We showed all the right qualities needed for a derby day game and played some good football today."
Chesterfield Xl v Rotherham: Mason; Slack, Broadhead, Whittaker, McNicholas; Partridge, Scully, Brock ( Morrison 75), Fereday ( Johnson 45 ) ; Mathers; Bowland.
Unused subs: Alexander; Maguire; Noel.