Three penalty saves at Bramall Lane, one from Paddy Kenny and two from Brad Friedel, left both sides still without a league victory this season.
Brad Friedel and Paddy Kenny salute eachother after the game
Referee Mike Dean was the centre of attention in a frantic last 20 minutes.
First Lucas Neill saw his penalty saved after Benni McCarthy had gone down theatrically, before Friedel matched his heroics against David Unsworth.
And, unbelievably, Dean found time to award another spot-kick - against Andre Ooijer - but Friedel denied Rob Hulse.
It was an astonishing end to what had been a lacklustre affair up until the death, though Blackburn might feel the better for the draw despite three apparently harsh penalties.
Unsworth was the victim of the first poor penalty call, Dean adjudging he had felled McCarthy even though the South African striker appeared to slip on his own studs.
United's protests were waved away but it mattered not when Kenny sprawled to his left to palm away Neill's spot-kick to send the home crowd into raptures.
Apparently keen to even the score, Dean then pointed to the spot at the other end when Zurab Khizanishvili was adjudged to have held back Hulse - only for Friedel to beat away Unsworth's low spot-kick.
And, to cap a stunning turn of events at the end of the game, the linesman flagged to award a penalty when Ooijer was harshly judged to have handled in chesting back to Friedel.
Once again though, the American proved unbeatable as this time Hulse found him too good to pass despite a fiercely-struck penalty kick.
There was no doubt that Friedel had earned Rovers the point having made a series of saves either side of his penalty heroics.
Hulse, Chris Armstrong and Michael Tonge all tested the veteran without success, failing to earn United what would have been a deserved victory.
Typically, with both sides searching for their first win of the season, it was a nervous match that bubbled under the surface for much of the game until Dean's late intervention.
Ironically, Dean had earlier been proved correct in waving away penalty appeals from United - one for a superb tackle by Robbie Savage on Hulse and one for a ball-to-arm appeal against Brett Emerton - while Blackburn unsuccessfully appealed for a spot-kick when Francis Jeffers went down under Chris Morgan's challenge.
Neill, given licence to roam from his left-back role, often proved Blackburn's front-runner in their rare attacks but he twice fired wide of the target when well-placed.
But all that was just a prelude to the bizarre ending to the match, which made heroes of Friedel and Kenny, though the result left both sides still in the bottom three.
Sheffield United manager Neil Warnock:
"Obviously I thought ours were penalties and theirs wasn't.
"Theirs was typical of an international player going down in the area after simply being briefed on and the only thing that was missing was a couple of dramatic somersaults.
"As for ours - the first was sheer stupidity from the boy that he pulled Hulse, while the second whether it was shoulder or arm, that's where Ooijer controlled it."
"For all that I enjoyed the game.
Blackburn manager Mark Hughes:
"I feel our play was more progressive and that we deserved at least a point.
"We are pleased that the two penalties have not cost us because I think the decisions were poor.
"Our keeper Brad Friedel has kept us in the game with those saves but he should never have been put in that position."
Sheff Utd: Kenny, Armstrong, Leigertwood, Morgan, Unsworth, Tonge (Alan Quinn 82), Jagielka, Sommeil, Ifill (Kazim-Richards 64), Hulse, Webber (Nade 17).
Subs Not Used: Akinbiyi, Kozluk.
Booked: Hulse, Tonge.
Blackburn: Friedel, Emerton, Khizanishvili, Ooijer, Neill, Bentley, Tugay, Savage, Pedersen, Jeffers, McCarthy (Nonda 72).
Subs Not Used: Brown, Mokoena, Gallagher, Peter.
Booked: Khizanishvili, Savage.
Ref: M Dean (Wirral).