Veteran Barnet striker Paul Furlong scored twice as the lowly Bees came from behind to stun play-off hopefuls Chesterfield in a 3-1 win.
Wade Small controversially fired the Spireites ahead but Furlong - who also missed a penalty - netted two volleys and Jake Hyde scored a header to hand Barnet their first home win in five matches.
Bees skipper Micah Hyde had a deflected shot well saved by goalkeeper Tommy Lee before Small's contentious goal put Chesterfield ahead in the 14th minute.
Assistant referee Neil Hair flagged for offside as Small drilled Ishmel Demontagnac's cut back past keeper Jake Cole, but referee Jarnail Singh overruled him and awarded the goal.
Furlong, 41, equalised for Barnet when he volleyed in Matt Lockwood's cross from close range in the 34th minute.
Jake Hyde nodded in Micah Hyde's cross to put the Bees ahead eight minutes later, before Furlong acrobatically volleyed Albert Jarrett's cross into the top corner to complete his brace on the stroke of half-time.
Furlong was denied a hat-trick when Lee tipped his 67th-minute penalty onto the crossbar, after Albert Adomah had been tripped in the box by Kevin Austin. Chesterfield pressed late on but Scott Boden headed wide from six yards and Derek Niven's volley was brilliantly saved by Cole at the death.
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