Francois Zoko scored a late winner for Carlisle as they came from behind to beat struggling Chesterfield.
The Spireites led when Drew Talbot's shot from eight yards out squirmed through keeper Adam Collin's hands and crept over the line.
Ben Parker levelled the scores on his Carlisle home debut when he headed home Jon-Paul McGovern's corner.
Zoko pounced on James Hurst's weak backpass and rounded Tommy Lee to slot home the winner from close range.
The result leaves Carlisle only outside the play-off places on goal difference, but Chesterfield remain bottom of the table.
VIEWS FROM THE DRESSING ROOM
Carlisle boss Greg Abbott told BBC Radio Cumbria:
"We've lost Lee Miller and we've lost Matty Robson and we've lost James Berrett at the moment, three players who've been a part of the successful start to the season.
"They're big players and they take some replacing. I tried to find the right formula.
"We just decided to change it round at half time. We went with the two up top to put them under pressure.
Chesterfield assistant manager Tommy Wright told BBC Radio Sheffield:
"As you can see from the game, we never looked in danger (of losing). We controlled the game.
"We probably looked like the team that was going to get the second goal, especially when Nicky (Ajose) came on.
"But we switched off from a corner and a back-pass and it's cost us. It cost us dearly.
"We've been good defensively the last few weeks, but you've got to switch on all the time against a team that's pushing for the play-offs. They're not going to give up, they're always switched on and the first goal was a real killer."