Jordan Slew sunk Bristol City with a superb late winner to keep alive Sheffield United's faint hopes of preserving their Championship status.
Brett Pitman opened the scoring direct from a corner before Lee Williamson's lucky ricochet drew the Blades level.
Nicky Maynard was sent off for the visitors and David McAllister rifled the hosts ahead.
Harry Maguire then saw red after conceding a penalty, which Pitman converted, before Slew slammed home.
Slew, 18, fired his first senior goal on his debut at Preston last week and followed up with a fine winner that lifts the Blades to within six points of safety with three games remaining.
The home side had begun the game full of purpose but were undone by Steve Simonsen's howler in the ninth minute.
The Blades goalkeeper had turned away Maynard's fierce shot for a corner and when Pitman delivered a right-footed inswinger to the far post, Simonsen flapped at the ball and contrived to deflect it over the goalline.
A prolonged torrential downpour made conditions difficult but the Blades still pressed and they turned the game on its head in the space of three minutes just before the break.
United deservedly equalised in the 40th minute in bizarre fashion. The ball pinballed around the City penalty area and visiting defender Jamie McAllister's attempted clearance rebounded off Williamson and into the net.
Two minutes later the visitors were reduced to 10 men when Maynard's two-footed tackle prompted a straight red card from referee Andy D'Urso.
A minute later, David McAllister fired home a brilliant first-time shot from the edge of the penalty area following Lewin Nyatanga's miskick.
McAllister then curled another fine effort towards the same corner, only for David James to turn the ball away at full stretch.
City's 10 men were almost back on level terms in the 52nd minute when Pitman's 25-yard free-kick came back off the post.
The Blades were reduced to 10 men themselves in the 59th minute when Jon Stead was brought down inside the penalty area by Maguire.
D'Urso showed the youngster a straight red card and Pitman placed the subsequent spot-kick into Simonsen's bottom left-hand corner.
Blades manager Micky Adams was roundly booed for immediately sending on defender Rob Kozluk for Williamson, arguably the game's stand-out player, while Pitman and City skipper Marvin Elliott spurned golden chances to put the visitors ahead.
But with four minutes left Henderson's knockdown from Matthew Lowton's cross was rifled home from 12 yards by Slew to hand Adams his third win in 20 league games as Blades boss.