United have been in and around the automatic places and the play-offs pretty much all season, and have had many threats for the coveted prize of instant promotion to the Championship.
Huddersfield, MK Dons and Sheffield Wednesday have all battled with the Blades for the majority of the campaign for second spot, but the rigours of the fight for promotion from the third tier has seen the Terriers and the Dons fall by the wayside, leaving only fierce neighbours Wednesday as any threat for second spot.
Blades boss Danny Wilson, who has steered his side to 26 league wins thus far, accepts it is now between the two Sheffield clubs in what is a four-game shoot-out for an automatic spot.
He said: "I think it is a fight between three clubs for the top two spots now. We have managed to put daylight between ourselves and Huddersfield, which is a bonus.
"Now, after a fantastic Easter period, we must concentrate on getting maximum points from another home game against Leyton Orient.
"We can't think about what we need because nothing has been confirmed mathematically and we will continue to go out and try and win every game.
"Nothing has changed all season; we don't think about what everyone else is doing, we concentrate on winning our games and seeing where that takes us."
Wilson, however, has refused to concede that Charlton are champions elect. He has maintained all season that the Addicks are still catchable.