The Burnley striker, a January transfer window signing from Brighton, was first to latch on to Michael Kightley's cross in the seventh minute and steered his header into Barnsley goalkeeper Luke Steele's top right-hand corner.
It was one of few clear-cut chances in the Clarets' 1-0 win and dealt the home side's Sky Bet Championship survival chances a huge blow.
It was a routine win in the end for Burnley, 10 points clear of closest rivals QPR in the race for the second automatic promotion place at the start of play.
Barnsley were a pale shadow of the side which had reignited their relegation fight with successive away wins at Reading and Yeovil in recent weeks.
Reds winger Dale Jennings' misdirected first-half shot was as close as they got all game, while Burnley striker Danny Ings, back after a five-game lay-off due to an ankle injury, and Barnes had chances to increase the visitors' lead.
Burnley went ahead with their first attack when defender Ben Mee set Kightley free down the left and the midfielder curled over a fine cross for Barnes to head home at the near post.
Barnsley responded through Jennings, but his effort was blocked after he had burst into the penalty area.
The visitors, roared on by an impressive and expectant following, carried a threat when ever they broke forward and Ings side-footed a volley narrowly over the crossbar.
Jennings blazed a half-chance off target following good work by Tomasz Cywka, but the home side were largely feeding off scraps against a well-drilled promotion-chasing outfit.
Barnsley began the second half with more purpose, but it was Burnley who carved out another chance, Kightley again charging into space and forcing an excellent save from Steele, low down to his left.
Barnsley boss Danny Wilson sent on substitute Rueben Noble-Lazarus for Jacob Mellis on the hour mark in a bid to kick-start his side, but it was an uphill struggle.
One particular Burnley challenge summed up the contest. Cywka raced on to a more promising pass, but ran into a brick wall, namely Michael Duff, and while the Pole was sent sprawling, the bigger Burnley defender came away with the ball.
Barnsley chased hard and harried gamely, but were limited on the edge of the opposition's area.
Barnes should have done better with midfielder Scott Arfield's cut-back and the Clarets forward then headed straight at Steele with a free header.
But it did not matter to the masses in the visitors' end, who were left to celebrate a 10th league win on the road this season.