Danny Welbeck rescued a draw for Brighton as 10-man Sheffield United survived relentless pressure to claim only their second Premier League point of the season.
Welbeck fired home from close range to cancel out Jayden Bogle's opener for United, who had John Lundstram sent off in the first half.
The Blades midfielder was initially cautioned for a studs-high challenge on Joel Veltman, but referee Peter Bankes upgraded the yellow card to a straight red after consulting his pitchside monitor.
The hosts had Chris Wilder's side pinned back inside their own half for the majority of the contest but failed to convert their chances, with Aaron Connolly, Neal Maupay and Leandro Trossard all spurning promising opportunities in the first half.