Chesterfield's relegation fears deepened after their winless run stretched to five games with defeat at promotion-chasing Exeter.
Jayden Stockley rattled in his 22nd goal of the season in the 39th minute and Alex Whitmore put through his own net to keep the Spireites seven points adrift of safety.
Andy Kellett came off the bench to give Chesterfield hope in the 83rd minute but there was no way back for Jack Lester’s side.
A fourth defeat in their last five games means Chesterfield have a mountain to climb as they attempt to cling on to their Football League status.
Spireites stopper Aaron Ramsdale was the busier of the two keepers in the opening stages, diving to his right to claw away Stockley’s low drive.
Chesterfield swept up the other end and Louis Dodds’ effort deflected out for a corner before Kristian Dennis stabbed a shot wide.
But Exeter carried the greater threat and a quick free-kick by Lloyd James sent Jake Taylor scampering into the penalty area – but Ramsdale was quick off his line to deny the Exeter midfielder.
The Spireites keeper came to the rescue again, scooping James’ effort out for a corner as Exeter continued to carve out a steady stream of chances.
But Chesterfield’s resistance was finally broken six minutes from half-time when Taylor delivered from the right and Stockley climbed highest to head home from the edge of the six-yard box.
The visitors were a whisker away from levelling with 58 minutes on the clock when James headed Chris O’Grady’s cross onto his own post.
The ball rebounded into the path of George Smith but his follow-up attempt forced Christy Pym into a smart finger-tip save.
Ramsdale produced a stunning save to keep out Pierce Sweeney’s free-kick as Exeter piled on the pressure.
But Chesterfield buckled again when Boateng’s deflected cross was turned into his own net by Whitmore.
The visitors pulled a goal back when Kellett converted Joe Rowley’s cross but they were unable to find an equaliser.
Exeter City: Pym, Wilson, Sweeney, Storey, Croll, James, Boateng, Tillson, Taylor, Simpson (Jay 62), Stockley. Subs not used: Jones, Archibald-Henville, Brunt, Seaborne, Edwards, Loft
Chesterfield: Ramsdale, Whitmore (Rowley 80), Nelson, McGuire, Barry, Smith, Reed, Weir (Kellett 67), Dodds, Dennis, O’Grady (Brown 73). Subs not used Anyon, Talbot, McCourt, Hines
Referee: Brendan Malone
Attendance: 3,560 (134)