Exeter completed a league double over an uninspiring Reds on a disappointing midweek trip.
It was back down to Earth with a bump for Barnsley, beaten away at Exeter City in Sky Bet League One, missing the chance to close in on the race for an automatic promotion spot.
It had been a promising first 45 for the Reds who dominated territory and looked the most likely to forge ahead in Devon.
But despite the superiority a clear-cut opportunity wasn't forthcoming. The best efforts in the opening quarter came from Herbie Kane and James Norwood who both dragged shots wide of goal from the edge of the box.
The home side hadn't looked an attacking threat barring a couple of corner kicks that were fruitless, but they took the lead regardless on 26 minutes.
A ball looked destined to go behind for a Reds goal kick until Jay Stansfield sprinted to keep it in. He got ever-so fortunate when his attempt to flick the ball beyond Jordan Williams deflected off the defender and into space that he ran onto before curling a great strike into the top corner to send the St James Park faithful into raptures.
But the Reds remained steadfast and just 10 minutes later, were level.
The set-piece quality of Luca Connell again proving pivotal as his inswinging delivery from central midfield found Bobby Thomas around 10 yards from goal and the central defender's guided finish found the top right corner to square the game going into the half time break.
HALF TIME: Exeter City 1-1 Barnsley
Sadly, it turmed out to be a poor second half from the Reds, with the Grecians regaining the lead five minutes into it as Stansfield easily beat Williams down the left before pulling back for an unmarked Harry Kite to slam home from just inside the box.
The lethargic display saw Michael Duff make four changes just after the hour mark with Max Watters, Josh Benson, Slobodan Tedic and Luke Thomas all introduced in an effort to salvage something.
Serbian forward, Tedic did have our best chance when his shot was thwarted by the legs of the goalkeeper but it was very much an off-night for the Reds.
Our hosts sealed all three points in the 89th minute when substitute Sam Nombe tucked home a penalty following Bobby Thomas' reckless tackle.
A night to forget for Duff's side, with a huge month ahead.
FULL TIME: Exeter City 3-1 Barnsley
Isted, Williams, B.Thomas, Andersen, Kitching (Cundy), Cadden, Phillips, Connell (J.Benson), Kane (L.Thomas), Norwood (Watters), Cole (Tedic).
Unused: Collins, Larkeche.
