Sheffield United forward Oli McBurnie netted a stoppage-time penalty to rescue a 2-2 draw in Sunday's Premier League home meeting with West Ham United.
The Hammers landed the first major blow in the 28th minute when Maxwel Cornet found the net to score his first goal for the club.
Despite being forced onto the back foot, the Blades pulled themselves through Villarreal loanee Ben Brereton Diaz, who celebrated his Premier League debut with a goal.
After going into the break on level terms, Sheffield United carried the greater threat in the second period until they were dealt a sucker punch in the 79th minute when James Ward-Prowse restored West Ham's advantage from the penalty spot.
However, the drama was far from over as Rhian Brewster and Vladimir Coufal were both given their marching orders, before McBurnie netted a 103rd-minute spot kick to ensure that the contest ended all square.
Although they salvaged a point, the Blades remain rooted to the bottom of the Premier League table, while West Ham stay in sixth position.
After missing the FA Cup replay with Bristol City, West Ham talisman Jarrod Bowen returned to the side for the trip to Bramall Lane.
The England international had an early chance to mark his return to the side with a goal, but he could only drag his left-foot strike harmlessly wide of Wes Foderingham's goal.
After seeing their opponents offer an early threat, the Blades had their open chance to open the scoring when a corner found the unmarked Auston Trusty, who guided his header straight at Alphonse Areola.
Trusty was made to rue that missed opportunity, as David Moyes's troops raced up the other end to open the scoring through Cornet.
The 27-year-old was on hand to fire past Foderingham after the ball deflected into his path from Danny Ings's initial shot.
Sheffield United responded positively to falling behind, and their persistence was ultimately rewarded with an equaliser in the closing stages of the first period.
William Osula saw his far-post header superbly saved by Areola, before Brereton Diaz pounced on the rebound to thump the ball past the West Ham goalkeeper.
After netting his first goal for the club, the Chile international had the chance to double his tally in the 58th minute when he latched onto James McAtee's defence-splitting pass.
However, with just Areola to beat, Brereton Diaz could only send his effort wide of the target to the frustration of the home support.
While Chris Wilder's side showed the greater intent following the half-time break, their hard work came undone when Gustavo Hamer was penalised for a clumsy foul on Ings in the Sheffield United box.
Ward-Prowse shouldered the responsibility to confidently dispatch the subsequent spot kick, sparking scenes of jubilation behind Foderingham's goal.
Matters got worse for the Blades in the 91st minute when substitute Brewster was shown a straight red card for a reckless challenge on Emerson.
Just as the Hammers appeared to be closing in on three points, Coufal was dismissed for a second bookable offence, giving the home side a semblance of hope.
That hope turned to real belief when referee Michael Salisbury pointed to the spot after Areola had clattered into McBurnie.
With the West Ham goalkeeper unable to continue, Lukasz Fabianski was thrown on to face up to McBurnie, who kept his composure under immense pressure to slot his penalty into the bottom corner.
Despite picking up a valuable point, the Blades are now winless in nine league matches, while the Hammers will have to reflect on a second consecutive draw.
