Wembley beckons for the Blades after Danny Wilson's side secured a play-off final berth at the expense of Stevenage.
In the play-off semi-final at the Lane, Chris Porter's late header sealed a first ever win over Stevenage, but more importantly, a chance of promotion.
Preparations immediately turn to the finale at Wembley on Saturday 26 May, when the Blades could be 90 minutes from an immediate return to the Championship.
Wilson named an unchanged starting XI but, notably, there were changes on the bench where Montgomery and McAllister replaced Ertl and Cresswell, who, after suffering a series of injuries of late, was unavailable due to an eye infection. Stevenage made one change with Shroot replacing Reid, who dropped to the bench.
United's formation from the first leg, 4-4-1-1, remained with Quinn again the most advanced midfielder, supporting lone striker, Porter. Judging by the pre-match rendition of the 'Greasy Chip Buttie' anthem, the fans were up for the clash and, despite Borough winning a corner in the first 30 seconds, the home players began at a high tempo, working a first chance on seven minutes. From a Hill cross, Williamson got in ahead of his marker to set up a header from Porter, who forced goalkeeper Day into a one-handed save.
The opening 20 minutes saw United firmly in the ascendency but a number of corners and open-play deliveries into the box was all that the home side had to show for the dominance. Doyle saw a lot of the ball early on and he made up a lot of ground to halt a break by Freeman around the half hour mark.
For United, Porter headed down a Hill cross before visiting defender Ashton sliced the ball onto the roof of his own net, whilst just before the break Williamson curled wide after Porter laid off.
McDonald, who was struggling with a hamstring problem before the game, needed treatment at the end of the first half and although he was quickly back on his feet, he was unable to start the second period - the midfielder was replaced by Montgomery.
United were quickly back on the offensive and went close on 48 minutes but, after Lowton and Williamson had combined on the right, a shot from Flynn was blocked by Lascelles and then, from a Porter cross, a shot from Williamson, arriving late in the box, was just wide.
The Blades, it seemed, were getting closer, and the Kop were on their feet on 57 minutes when Lowton's forward ball was controlled by Porter for Flynn to smash a half volley from 25 yards, which was just wide. Stevenage's first effort on the half arrived just before the hour but Freeman, who received a pass from Laird, shot at Simonsen at the near post.
The hardworking Quinn curled over on 62 minutes, after good work from Williamson, who then fired the next shot, a free-kick, into the Kop. Stevenage, for all their defensive endeavours, were a threat on the break and after Freeman held off Lowton, who was later booked, the ball broke for Laird to fire a shot which Simonsen needed to tip over. It was followed by a 30-yard free-kick from Bostwick, which the Blades goalkeeper held.
United went back on the attack and in the final ten minutes the chances continued to pour down on the Stevenage goal. A Lowton left-footer was blocked and Hill, with a first-timer from 35 yards, went close. Quinn also had an effort saved by Day before the decisive moment arrived with five minutes remaining.
From a Simonsen kick, Montgomery won the initial header and Porter, Quinn and Lowton, who delivered the cross, were involved before PORTER got in ahead of the visiting central defenders to beat Day with a close range header, in front of the Kop.
Naturally, Stevenage then committed men forward, captain Roberts made himself an auxiliary centre forward, whilst Reid's header from a cross was straight at Simonsen. Three minutes of added time was announced but United were smart in the extra period and held on, the final whistle signalling a pitch invasion by Unitedites.
Blades: Simonsen, Lowton, Doyle, Flynn, Williamson, Collins, Maguire, Porter, McDonald (Montgomery 45), Quinn, Hill.
Unused: Howard, Taylor, McAllister, O'Halloran.
Stevenage: Day, Wilson, Laird, Ashton, Byrom (Reid 87), Roberts, Freeman, Bostwick, Agyemang (Beardsley 63), Lascelles, Shroot (Mousinho 57).
Unused: Julian, Charles.