A late first half goal and two late second half goals condemned Chesterfield to defeat at also relegated Barnet in the club's first visit to The Hive.
Former AlfretonTown striker Joh Akinde headed the opener on42 before ex-Spireite Richard Brindley scored on 82 and Alex Nicholls completed the goals with a late blockbuster.
Ian Evatt made five changes from the side that beat Newport County in midweek, Sid Nelson and Andy Kellett were injured, George Smith and Louis Reed were on the bench whilst Aaron Ramsdale missed out allowing Joe Anyon to play for the first time since breaking his arm. Jordan Sinnott also returned after a long injury spell whilst the other three incomers were Tuesday's three playing subs Jacob Brown,Robbie Weir and Alex Whitmore.
Kristian Dennis forced the game's first save following an error at the back from the hosts but his stretched shot was pushed wide for a corner by Craig Ross.
Sinnott was on target from range before Anyon twice had to deny Akinde and Jerome Binnom-Williams had to clear a shot off the line.
Brown chipped just over from a great position and Alex Nichols had a box-edge effort deflected wide before Brown tapped In a Louis Dodds angled drive only for an offside flag to deny him his first Spireites goal.
Anyon made a stunning right sided save to paw out an Akinde header before Bradley Barry pulled a left-footer inches wide after a strong run.
Alex Weston rattled the bar from18 yards, Anyon saved Akinde's follow up and Barry hit over just before Akinde headed downwards to score on 41 fromWeston's ball in after a short free-kick near the halfway line.
Ricardo Santos headed just wide for a corner and fellow central defender Michael Nelson hit high from The Bee's next corner as the hosts looked to add to their lead.
Sinnott shot over before being replaced by the returning Giles Coke and Joe Rowley came on for Dodds with the sub volleying over soon after his introduction.
Coulthirst hit the side netting before Bees's late goals, both angled shots from the right, Brindley with a low shot and Nicholls with a long range cracker on 88.
Teenager Luke Rawson came on for his senior debut but there was little for anyone to celebrate as Morecambe's point at Coventry ensured both of these sides will meet in next season's National League.
Barnet: Ross, Brindley, Santos, Nelson, Tutonda, Akpa Akpro, Weston, Sweeney, Nicholls, Akinde, Coulthirst. Subs: Legg, Clough, Watson, Taylor, Bover, Shomotun, Payne.
Chesterfield: Anyon, Talbot, Whitmore, Maguire, Binnom-Williams, Barry, Weir, Sinnott, Brown, Dodds, Dennis. Subs: Parkin, Coke, Rowley, Smith, Reed, Rawson, Holmes.
Ref: Dean Whitestone
Attendance: 5539 (563 from Chesterfield)