Morecambe recorded their first home victory of the season as Chesterfield left the Globe Arena empty-handed.
Gary McDonald's far-post volley from Richard Brodie's left-wing cross put the hosts ahead just before half-time.
Brodie also set up the second goal, getting the better of Terrell Forbes, and Lewis Alessandra volleyed past Richard O'Donnell from close range.
Craig Westcarr twice went close for Chesterfield, while Neal Trotman put a free header wide.
VIEW FROM THE DRESSING ROOM
Morecambe manager Jim Bentley told BBC Radio Lancashire:
"There wasn't much in it in the first half. We were evenly matched, but goals change games.
"We got the goal at the crucial time, we came out in the second half and scored a great second goal.
"We could have had one or two more but I'll take 2-0, a clean sheet, three points and the right result."
Chesterfield caretaker manager Tommy Wright told BBC Radio Sheffield:
"For the first 40 minutes I was delighted. I thought we broke, created chances.
"In the second half, we were not good enough, we were second best all over the park.
"Morcambe were far the better team in the second half and we looked like we lost heart."