The gap between second and third place increased tonight as, in spite of having more of the chances, Forest suffered their sixth away defeat in a row.
Forest dominated much of the first half and created more chances, but it was the home side who found the back of the net and went in at the break a goal up.
Again in the second half Forest had more of the chances. A penalty gave Barnsley their second goal of the evening, but when Forest got a goal back they looked good enough to get an equalizer, but the home side held on to take all the points.
The game started quietly in an equally quite stadium, with just the noise of the travelling supporters breaking the silence.
Forest looked the more confident side although the closest anyone came in the opening minutes to getting a shot in was
Chris Cohen's effort in the eighth minute which went wide from 20 yards out.
But it was Barnsley who took the early lead, with their first real move of the game. It came from a long free kick which was flicked on to Daniel Bogdanovic whose looping header went over
Lee Camp and into the top corner.
And they came close to another when Adam Hammill curled the ball in, forcing Camp to dive to his left to palm the ball round the post.
Forest created a chance with a superb chip forward by
Radoslaw Majewski to
Dele Adebola, who was clean through on goal. He lifted the ball round the keeper but then hesitated and went down as he got a touch on the ball and sent it wide.
Adebola missed another golden opportunity after getting past the final defender and going one-on-one with the keeper. Luke Steele ran off his line making it easy for Adebola to lift the ball over him, but again his effort was off-target.
Robert Earnshaw produced some good footwork after a great ball through to him by
Guy Moussi but in the end the Forest striker was crowded out.
Forest continued to look the better side until some late pressure from Barnsley just before the break.
Barnsley had a chance early in the second half after Foster was blocked by
Wes Morgan and the ball fell to Bogdanovic who side-footed it wide of the post.
Forest came close to an equalizer from a free kick when Cohen slipped the ball to Majeweski who tried a long-range effort which flew towards goal and seemed to hit the base of the post before being cleared.
And they came close again after an initial effort in by
Chris Gunter was punched out by Steele to the edge of the box and the ball fell to Cohen, but he hit it on the rise and the effort went wide.
Barnsley were awarded a penalty when
Robert Earnshaw allowed Filipe Teixeira to get past him and then brought him down from behind, earning him a yellow card.
Bogdanovic took the penalty and sent Camp the wrong way to put the home side two up.
Nathan Tyson became the first substitute of the night, replacing George Boyd who had done little to impress during the game.
And Adebola followed him off soon after, replaced by
Dexter Blackstock.
A two-fisted save by Steele prevented a powerful shot by Majewski from finding the back of the net. The ball came back into play and Cohen's effort went straight to the Barnsley keeper.
Forest had a goal back with 12 minutes remaining after Majewski's cross from the left found Blackstock. His bullet of a header was saved by Steele but he only parried it straight back to Blackstock who poked in the rebound.
With time running out, Forest surged forward at every opportunity. And they thought they had the equalizer in the 90th minute when the ball went over the line but the referee judged that Steele had the ball knocked out of his hands inside a crowded box.
Nottingham Forest: Camp(C), Gunter, Morgan, Wilson, Perch, Cohen, Moussi(Anderson 81min), Majewski, Boyd(Tyson 68min), Earnshaw, Adebola(Blackstock 74min)
Subs not used: Smith, Chambers, McGoldrick, Garner
Bookings: Earnshaw 64min, Majewski 67min
Scorer: Blackstock 78min
Barnsley: Steele, Hassell, Foster, Shotton, Potter, Teixeira, Colace, Doyle, Hammill(Hallfredsson 25min), Macken, Bogdanovic(Hume 75min)
Subs not used: Preece, Anderson, Butterfield, Gray, Thompson
Bookings: Hammill 19min, Teixeira 71min, Hume 84min
Scorer: Bogdanovic 12min, pen 65min
Referee: K Friend
Attendance: 13,174