Sheffield Wednesday scored two late goals in the space of just four minutes to rescue a point in a stunning Steel City derby climax at Bramall Lane.
The Blades were two up inside 20 minutes after Stephen Quinn found the top corner, before Ched Evans headed the second from Lee Williamson's cross.
But Ben Marshall set up Chris O'Grady to score with an 82nd minute header.
And top scorer Gary Madine outjumped home keeper Steve Simonsen to claim the Owls' scrappy 86th minute leveller.
That was a major disappointment for former Owls boss Danny Wilson, taking charge of his first derby since being sacked as Wednesday manager in March 2000 - especially as he felt that Simonsen had been fouled.
Quinn opened the scoring on 11 minutes, seizing on a rebound to fire home after Evans' low shot had been deflected on to a post.
O'Grady then wasted a gilt-edged chance to equalise, hitting the post from close-range after Simonsen had spilled the ball.
The miss looked to have proved costly when Evans put United 2-0 up just a minute later, beating Owls keeper Stephen Bywater with a near-post header.
As Wednesday pressed, James O'Connor steered a free header off-target and Ben Marshall twice threatened.
But, in a pulsating finish in front of a 28,136 full house, O'Grady pulled one back with a far post header before Madine headed the equaliser after beating Simonsen to a high ball into the box.
The point for Owls boss Gary Megson in the boyhood Wednesday fan's first Steel City derby keeps his side five points clear of the Blades, despite the blow of dropping to third in League One.
The two sides also drew when they last met in the Championship in April 2010, sharing a 1-1 stalemate when the Owls were just two games away from being relegated to League One.
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Blades manager Danny Wilson told BBC Radio Sheffield:
"We've defended very well for 85 minutes but the referee's made a howler and they've got away with it.
"The one time you want protection from the ref, you don't get it. It was a bad decision. He's smashed him out of the way, the referee put his whistle to his mouth, then took it away.
"What I want to know is why a 25-year-old was put in charge of a game of this magnitude. A lot of more experienced referees might have seen what went on. I've made a complaint about the decision to put him in charge."
Owls manager Gary Megson told BBC Radio Sheffield:
"I'm obviously pleased with the fact that we've not got beat, having been two down with eight minutes left, but not pleased that we were two down in the first place.
"They've had two shots on target. We've had 10. And to find ourselves two down at half time was hard to swallow.
"But, not being wise after the event, I always felt that, if we scored the next goal, then I expected us to get the next too and that we wouldn't get beat."