Leon Clarke scored the first hat-trick of his career to make it three consecutive victories for Chesterfield as Carlisle went down 4-1 to lose their unbeaten away record in League One.
Clarke, who had scored in his previous two games following his loan move from Swindon, twice put Chesterfield ahead in an entertaining first half before scoring again soon after the break
Lee Miller had equalised for Carlisle but the striker limped off six minutes before half-time and Craig Westcarr sealed victory with a powerful header.
Chesterfield caught Carlisle cold in the 3rd minute when Westcarr set up Clarke from close range but Miller replied with a 20th minute volley when keeper Greg Fleming failed to punch clear.
Clarke restored his team's lead with a glancing header from 10 yards six minutes later and bundled the ball home when Carlisle failed to deal with a free kick in the 51st minute.
Any hope of a comeback vanished in the 65th minute when Nathan Smith chipped the ball in from the left and Westcarr headed into the roof of the net.
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