The result also ended Lee Johnson’s unbeaten start to life as Barnsley boss and leaves the Reds outside the top six with games fast running out.
United, however, underlined why they have been in the promotion hunt all season with a professional performance.
Goals from Steven Davies and Jason Holt capped a fine afternoon’s work for Nigel Clough’s Blades, much to the delight of the 5,322 Unitedites in the 17,532-strong crowd at Oakwell.
After earlier hitting the top of the cross bar with a header from Bob Harris’s raking free-kick from the left-back position, Davies found his range with a looping header on 42 minutes, this time from the opposite flank and the boot of right-back Keiron Freeman, whose floated free-kick was met with precision by the striker.
United carried much greater threat on the counter in the second half as Barnsley’s energetic attack struggled to create any clear-cut chances.
And Clough’s men had their rewards on 71 minutes when Holt fired in with a fierce volley after Barnsley had failed to deal with Harris’s left-wing throw and Chris Basham’s subsequent flick-on.
Sheffield United first-team coach Andy Garner said: “They’re on a great run and it was a big game for both and I think we got the team spot on.
“We deliberated for a long long time on Friday. There were a lot of disappointed players not playing today but we wanted to be a bit more physical today and it paid off.”
Johnson said: “We were poor today and we deserved to lose. We didn’t do enough, as individuals and as a team.
“it’s disppointing because we’ve been on a good run. Everyboyd had whipped it up into a frenzy but it very much feels like a balloon has popped.
“You get that in football, but we lacked that bit of savvy to make a game of it. Maybe if we scored the first goal...but I have to be honest we didn’t look like we were going to do that today.”
Barnsley: Wildsmith, Holgate, Cranie, Nyatanga, John; Scowen, Pearson, Hourihane (Jennings 70), Stewart (Smith 70); Winnall, Ibehre (Hemmings 76). Unused substitutes: Dibble, Berry, Bailey, Cowgill.
Sheffield United: Howard, Freeman, Brayford, Kennedy, Harris; Flynn (Doyle 89), Basham, Coutts, Murphy; Holt (Scougall 88), Davies (Done 54). Unused substitutes: Turner, Baxter, McNulty, McEveley.
Referee: A Madley.