The Blades have done it again.
For the second successive year, Nigel Clough has guided the Blades into a major semi-final - this time Southampton - fifth in the Premiership - were beaten in the Capital One Cup quarter-final.
Marc McNulty touched home a Bob Harris free-kick to earn the Blades a deserved win.
Both managers made five changes following weekend encounters. For the Blades, Basham, Cuvelier, Reed, Campbell-Ryce and McNulty came in. McCarthy and O'Grady were unavailable due to being cup-tied, whilst Baxter, Higdon and Kieran Wallace dropped to the bench.
In a frantic opening, the Blades more than matched their Premiership visitors in the opening half hour and the early chances were around Forster's goal. On four minutes the Saints goalkeeper spilled Campbell-Ryce's free-kick but the subsequent effort, involving McEveley and Basham, struck the top of the crossbar.
Another Campbell-Ryce cross caused problems and Cuvelier's free-kick on 20 minutes was just over after he was fouled by Fonte. Southampton's first opportunity was from a Ward-Prowse free-kick but United scrambled clear.
The visiting side's Clyne and Mane were booked in the space of a minute for fouls on Harris and Murphy respectively as the Blades maintained the tempo and Reed was the next to go close, firing just over on 33 minutes. Basham was the next to burst out of his defensive position, powering down the right before delivering a cross which Cuvelier sliced wide.
As half-time approached, the game became fractious, interrupting United's rhythm, and Harris was
booked for a foul on Long, who then provided the cross for the final chance before half-time but Mane's shot was wide.
Adams was introduced at half-time for his debut and there was a frantic start to the second period. Murphy flashed a shot wide for the Blades, whilst at the other end there was a penalty appeal and Ward-Prowse tried his luck with a header and then a shot from the edge of the box.
On 55 minutes United again went close, following a quick Harris free-kick. A cross-shot from Murphy saw McEveley challenge in the air but Forster palmed away and the follow up from Adams was blocked by Clyne.
Cuvelier and Basham were booked for fouls and Ward-Prowse fired a free-kick over before United regained control. Adams did well to recycle possession but Forster pushed over Doyle's first time effort before the temperature was cranked up...
Mane - already booked - fouled Reed on the edge of the box, in fact the Saints man was in the box, but referee Oliver awarded a free-kick, inches from the 18-yard line. Harris took responsibility and his powerful low drive beat the wall and squirmed away from Forster and was arguably going to cross the line before McNULTY forced home in front of the Kop.
As United celebrated, referee Oliver had a chat with Clough and Chris Morgan, the latter being asked to leave his position on the bench.
A backlash from the Premiership side was expected but Howard kicked away an effort from Mane following Wanyama's pass, whilst McNulty had a chance to claim a second on 72 minutes but Forster saved with his body.
Baxter replaced Cuvelier and with ten minutes to go Wallace took over from Reed, and although there was a tension in the air late on, the Blades looked comfortable in protecting the slender lead, emphasised by the fact that United went close twice in one move on 87 minutes, first Murphy and then McNulty.
Howard calmly collected a free-kick into the box as the referee's watch approached 90 minutes and Gardos, the last man, was sent off for pulling down McNulty. Four minutes of added time was announced before the subsequent free-kick from Baxter, which was wide.
However, late bombs into the box were repelled and the Blades fans celebrated another cup success.
Blades: Howard, Harris, Basham, Flynn, Doyle, Murphy, McNulty, McEveley, Campbell-Ryce (Adams 45), Reed (K. Wallace 80), Cuvelier (Baxter 73).
Unused: McGahey, Higdon, Turner, Kennedy.
Southampton: Forster, Clyne, Schneiderlin, Gardos, Fonte, Long, Mane (Mayuka 71), Wanyama (Alderweireld 74), Ward-Prowse, Bertrand, Targett (Isgrove 45).
Unused: Davis, Yoshida, Reed.