West Ham United wasted a golden opportunity to move within three points of Tottenham Hotspur in fifth place by conceding a stoppage-time penalty to Sheffield United.
A moment of madness saw Alphonse Areola - who was injured in the incident - foul Oli McBurnie in the dying embers. The Blades striker slotted the resulting spot-kick past Lukasz Fabianski to snatch a late draw.
David Moyes made three changes from the side that lost 1-0 at Bristol City in the FA Cup. Much of the pre-match discussion centred around how the Hammers would cope without talisman Mohammed Kudos, currently away on African Cup of Nations duty.
But it was his replacement, Maxwel Cornet, who broke the deadlock against the run of play. The Ivorian started his first Premier League game of the season and sent a reminder to Moyes with a well-taken strike.
Ben Brereton Diaz would soon equalise and, for much of the contest, the Hammers appeared to be carrying a hangover from the shock Ashton Gate defeat.
West Ham looked laboured in the second half and it was the hosts who were most likely to snatch all three points. But a moment of brilliance from Danny Ings - who also turned provider for Cornet's opener - earned West Ham a 78th-minute penalty.
James Ward-Prowse buried home with aplomb and West Ham seemed likely to coast home to a gritty away win. But a hectic final 10 minutes saw red cards to Rhian Brewster and Vladimir Coufal before the Blades levelled from the spot.
One final moment of drama came in the 113th minute when Hammers fans were adamant they deserved a penalty. Jarrod Bowen was dragged to the floor but referee Michael Salisbury waved away the protests. Here are your LondonWorld player ratings following the 2-1 win at Bramall Lane.
1. Alphonse Areola - 6.5
A safe pair of hands when called up until the final minute. He gave away the penalty for a 50/50 challenge which has stoked controversy on social media.
2. Emerson - 6
Struggled to cope with McAtee. Not his finest hour.
3. Konstantinos Mavropanos - 7
Continues to look assured at the heart of West Ham's defence. Not at fault for either goal.
4. Kurt Zouma - 6
Erratic at times, composed in others. Almost scored from a header early on. Could have done better for the first goal.