The Blades have already faced Doncaster Rovers (won 2-0) and Sheffield Wednesday (lost 1-0) on their respective grounds and have yet to go head-to-head at Bramall Lane - but this contest was more high tempered than previous derbies between the two clubs.
United had taken the lead through James Beattie as early has the 19th minute, stabbing home at the far post following Danny Webber's square ball before Ugo Ehiogu and Anderson De Silva were both shown immediate red cards for there tug of wars in the Tykes penalty area.
All three points were sealed late on in the 85th minute when Beattie slammed home his penalty, former Blade Robert Kozluk handling in the box before substitute Keyode Odejayi gave the Reds faithful a life line two minutes later.
Despite the visitors taking the upper hand in this South Yorkshire derby it was the hosts whom got off to a start; Martin Devaney caused chaos for United throughout the game with Sun Jiahi motionless to stop the winger in what was hardly the Chinese Internationals finest hour - the winger flew past his marker and proved a low shot which Kenny was equal to.
Then, Simon Whaley, a debutant for the Tykes twisted and turned before his effort cannoned off team mate Iain Hume and away from danger, at the other Beattie came close to scoring when he latched onto Stephen Quinn's left cross at the far post only to head narrowly wide.
But it wasn't long before the 6,200 travelling fans were celebrating when Danny Webber dinked on the right hand side to produce a stunning cross where the unmarked Beattie scored the easiest goal of his career; sliding in at the far post to make it 1-0.
Moments late Beattie almost doubled his tally for the day, his long range effort looked goal bound but a stooping Heinz Muller guarded his goal at the far post to par away.
The match was thrown into the limelight in the 28th minute when a clash of head butts between Ehiogu and De Silva has they awaited a Blade free-kick; referee Andy D'Urso had no option to dismiss the pair for violent conduct. With an absent Ehiogu the Blades were forced into a change - Matthew Kilgallon coming on for Anthony Stokes.
At the latter stages of the first half Barnsley tested their metal against the Blade, Hugo Colace's long range powerful shot was hit away by Kenny; Jamal Campbell-Ryce then flung his 25 yard effort over the bar before the referee ended the half.
The second was less subdued than its previous 45 minutes but United did enough in the end to secure all three points - following a high tempered and exciting first half the opening exchanges in the second were comparing boring.
Former Blade Rob Kozluk set up a one-two with Mosstto only to fire straight at Kenny - the home side tried once one as they had a string of attacks, Davaney heading tamely at goal after meeting Kozluk's centre.
Barnsley had waves for a penalty turned away when Darren Moore was unheeded by former Tyke Chris Morgan in the box but D'Urso disagreed otherwise.
Muller then twice almost allowed the Blades to extend their lead when the German keeper rushes out of the box with the ball at his feet, he was tackled twice by Quinn but quick and slick Barnsley defending saved their bacon. Striker Keyode Odejayi was brought on for Booby Hassell in the 67th minute.
The game looked set to patter out until the game sprung into action once more with eight minutes left - a long cross into the box was brought down by Kozluk, and after some confusion the referee awarded the penalty (two minutes later) following advise from his assistant.
James Beattie stepped up in formidable fashion, he turned his back to goal walked away and like and eagle swooping down to meet its pray he turned round and blasted the ball deep into the bottom left hand corner.
The victory looked set in stone but two minutes, lack lusted defending allowed Barnsley a way back into the game - Whaley swung in a centre which was met by the head of Odejayi who finished off inside the 6 yard area. The referee added five minutes at the end but United hung to claim all three points.