The long unbeaten home run was ruined by an outfit which is quickly becoming United's bogey team.
A goal from Paul Hayes in first half injury-time gave Scunthorpe the points and also their first ever victory at Bramall Lane.
The intense second half pressure ultimately proved fruitless leaving United in 10th position in the Championship table.
Henderson and Yeates returned to the starting line-up for the Sunday lunchtime clash, the duo sufficiently recovered from injuries to take their place in the team at the expense of Little and Stewart, who both dropped to the bench. Scunthorpe's former Unitedite, Forte, was only amongst the Iron's substitutes.
Sunshine and a strong breeze welcomed the sides onto the lush-looking pitch but it was a subdued start. Both teams only managed one notable attack each in the first 15 minutes but Taylor's timely tackle prevented McDermott from making progress and a neat United move involving Harper, Quinn, Henderson and then Quinn again resulted in the latter's delivery flashing across the face of goal.
McCann's 30-yard free-kick, which was gathered at the second attempt by Simonsen in front of the Kop, preceded a spell of pressure by the Blades and both Quinn and Yeates sent in enticing crosses from the flanks.
On 18 minutes, from a Yeates corner, Connolly's prodded effort was cleared off the line by Mirfin and, after United's wide players had switched wings, an unmarked Yeates headed over after drifting in from the left to meet Cresswell's pinpoint cross.
A number of passing movements encouraged United's fans but the front two of Cresswell and Henderson were being well-marshaled, whilst a mistake almost handed the visitors the lead. Just after the half-hour Bartley's short back-pass put Thompson in the clear but Simonsen saved with his body and then gathered.
Yeates curled a free-kick just wide with Murphy rooted to his spot in the middle of the goal and, at the other end, Woolford cut in from left but was off target with his shot.
Four minutes of additional time at the end of the first half was announced and Scunthorpe took advantage to grab the lead. The lively McDermott got the better of Nosworthy down the visiting side's right and the pull-back was ideal for HAYES, who managed to beat the diving Simonsen with the aid of a deflection off Bartley.
The goal left the crowd frustrated and after the interval there was another quiet start to the half, although Connolly's cross caused problems in the Scunthorpe box.
Just eight minutes of the second half had elapsed before Blackwell made his first change, introducing Camara for Harper, which also prompted a change around in the midfield.
Yeates had a free-kick tipped over by Murphy, following McCann's foul on Quinn, and soon after Cresswell, now on the left, fired wide. United's second change was switching Little and Yeates, whilst Scunthorpe's first replacement was O'Connor taking the place of the injured McCann.
Expectedly, United were applying most of the pressure. Little's first contribution was to swing in a free-kick which Bartley headed over and then Camara could not get enough of a touch to a right wing cross on 65 minutes.
Scunthorpe remained a threat on the break and it took a one-handed save from Simonsen to keep out Thompson after another neat McDermott pass, but United were quickly back on the offensive with Little almost tricking his way through the visiting backline.
Forte was introduced with more than 15 minutes remaining and he almost squeezed between Bartley and Nosworthy within seconds of being introduced. The former United junior also picked up the game's first booking, for a foul on Little.
At the back post Henderson headed a Little free-kick onto the top of the crossbar but the home side's offensive options were hit on 78 minutes when substitute Camara again hobbled off. Williamson was Blackwell's final attacking option.
The final ten minutes saw almost constant Blades attacking, although getting through to Scunthorpe goalkeeper Murphy was a problem due to a solid defensive performance by the visitors. On 85 minutes Little's corner was met by Bartley but Hayes headed clear and Henderson was deemed offside when he connected with another Little cross.
Five minutes of injury-time offered hope to Blades fans and three corners in quick succession kept the pressure on but Murphy did well to hook Bartley's header around the post and hold another delivery into a crowded box. The last chance was an ambitious long-ranged effort from Nosworthy, which failed to trouble the Iron goalkeeper.
Blades: Simonsen, Montgomery, Nosworthy, Henderson, Yeates (Little 59), Harper (Camara 53, Williamson 78), Taylor, Cresswell, Bartley, Quinn, Connolly.
Unused: Bennett, Stewart, Seip, Lowton.
Scunthorpe: Murphy, A. Wright, Williams, Togwell, McCann (O'Connor 61), Hayes, Thompson, Mirfin (Canavan 34), Woolford, McDermott (Forte 74), Raynes.
Unused: May, J. Wright, Lillis, McNulty.












