Hungary international Istvan Ferenczi's double helped lift Barnsley out of the relegation zone at the expense of fellow strugglers Hull, who went down 3-0 at Oakwell.
Ferenczi opened the scoring in the first half when he benefited from a fortunate rebound and slack defending after 16 minutes.
Simon Davey's team doubled their advantage a minute after the restart when Ferenczi's compatriot Peter Rajczi cashed in on more ponderous Hull football to sidefoot Barnsley into what proved an unassailable position.
Barnsley completed the scoring when the unmarked Ferenczi thumped home a header after 76 minutes.
Phil Brown's men, who were also hit by injuries to two key players, showed a short-lived appetite for a battle and can also be considered unlucky to have gone a goal down against the run of play.
But their shortcomings in front of goal were underlined all evening as Nick Colgan, who was replaced by reserve goalkeeper David Lucas at the interval, were not seriously tested from a side who should be scrapping for their lives.
Conversely, Barnsley never missed a trick and opened the scoring with their first foray into the visitors' half.
Brown is sure to have something to say about the nature of his team's concession, however, after Colgan's huge punt upfield was unconvincingly dealt with by Michael Turner.
The former Brentford centre-back's tame clearance ricocheted kindly off Ferenczi and into the path of the same player, who prodded the ball through Boaz Myhill's legs from seven yards.
Brown's gameplan was further disrupted when Andy Dawson and McPhee sustained injuries and had to be replaced by Danny Coles and Darryl Duffy.
It was Coles who had a hand in Hull's best chance of the game, however, when his fine cross from the right should have been buried by former Barnsley striker Jon Parkin, who instead headed wide.
If Davey was left to rue his misfortune after Colgan was substituted by Lucas at half-time, the Barnsley boss was all smiles 60 seconds after the restart.
David Livermore was foolishly dispossessed just outside his penalty area, which enabled Rajczi the opportunity to power through on goal and slot the ball past the motionless Myhill.
Hull replaced the ineffectual Parkin with Dean Windass in a bid to salvage a cause that was effectively lost once Rajczi struck.
But other than Forster's overhead kick off Ray Parlour's corner and Livermore's precise free-kick that was headed clear by Martin Devaney, Brown's players looked devoid of ideas.
And with Hull naively pressing forward, Ferenczi put the seal on an adroit performance when he headed home Brian Howard's cross to confirm Barnsley are back in business after three consecutive defeats.
Hull, however, have now collected just two points from their last five games and face a grim task at home to Birmingham on Saturday judging by this worrying display.
Teams:
Barnsley Colgan (Lucas 46), Hassell, Paul Reid, Nyatanga,Heckingbottom, Devaney, Togwell, McCann, Howard,Ferenczi (Richards 88), Rajczi (Kyel Reid 82).
Subs Not Used: Jones, Atkinson.
Booked: Nyatanga, Hassell.
Goals: Ferenczi 16, Rajczi 46, Ferenczi 76.
Hull Myhill, Ricketts, Turner, Delaney, Dawson (Coles 20),McPhee (Duffy 31), Ashbee, Parlour, Livermore,Parkin (Windass 52), Forster.
Subs Not Used: Duke, Elliott.
Booked: Delaney, Duffy.
Att: 12,526
Ref: A D'Urso (Essex).