United's return to Premier League action ended with a point, in controversial circumstances, after a 0-0 draw at Aston Villa.
The Blades appeared to have taken the lead towards the end of the first half when an Ollie Norwood free kick seemed to have been carried over the line by Villa stopper Orjan Nyland. The 'buzzer' did not vibrate to indicate a goal, but replays showed the ball had in fact crossed the line as United were denied.
Blades boss Chris Wilder had to do without duo Jack O'Connell and John Fleck who were missing after sustaining contact injuries in training. Jack Robinson was handed a first Premier League start whilst Sander Berge returned in midfield.
United's bench was also boosted with Leon Clarke and Jack Rodwell as new regulations allowed for nine subs to be named.
Following a moment of silence for those who sadly passed away due to COVID-19, the game opened up with both teams showing solidarity to the Black Lives Matter movement by taking a knee for the opening 10 seconds in a powerful show of support.
Both sides started on the front foot with John Egan heading the first half chance wide from a long throw by Robinson.
Villa's Keinan Davis started brightly and it was his low cross that resulted in the game's first corner. The initial delivery was cleared but as Villa returned the ball it fell kindly for Conor Hourihane whose low strike was parried by Dean Henderson.
On 11 minutes Jack Grealish's deep corner was kept alive by Kortney Hause but Davis headed wide under pressure from Berge.
Whilst not creating anything clear cut, Villa threatened again when John McGinn connected to a low Grealish free-kick but his header was comfortably held by Henderson.
Midway through the half Villa's Douglas Luiz was first into Michael Oliver's book after he tripped Oli McBurnie as United threatened a counter.
With 10 minutes remaining until half-time, Villa earned another half-chance but Hause headed over.
John Lundstram joined Luiz in the book after stopping a restart, before the half's controversial moment.
United won a free-kick on the left and Norwood's spiralling centre looked like a routine take for Villa 'keeper Nyland. As he went to make his claim the 'keeper almost fumbled the ball before bumping into his own player, Davis, appearing to then carry the ball over the line. There was no goal-line intervention, and referee Oliver waved play on, despite replays showing the ball crossing the line.
Villa created another opportunity at the start of the second half when Matt Targett weighted a perfect ball forward into the path of Davis. The striker created half a yard of space before firing in a shot at the near post which was turned away by Henderson.
Soon after a teasing corner from Hourihane found Davis in space but the striker's header was weak and easily held by Henderson.
The hosts continued to carry the greater threat as Grealish released Anwar El Ghazi down the right. The low cross into the six-yard area looked dangerous but at full stretch Davis failed to connect.
Henderson was then called into action as Grealish teed up McGinn from distance, but the United stopper flung himself to his left to make a stunning save.
Wilder made a double change introducing Luke Freeman and David McGoldrick in place of Berge and Billy Sharp.
United then created a half chance when Norwood's corner was headed towards goal by McBurnie but straight at 'keeper Nyland.
Lys Mousset was introduced late on, but understandably, the pace of the game decreased as the match entered its final stages.
Neither side was able to break the deadlock, with both teams having to settle for a clean sheet and a point.
Villa: Nyland, Konsa (El Mohamady 76'), Hause, Mings, Targett, Hourihane, Douglas Luiz, McGinn (Nakamba 76'), El Ghazi (Trézéguet 69'), Davis (Samatta 69') Grealish.
Unsued: Taylor, Bastón, Jota, Reina, Vassilev.
United: Henderson, Baldock, Stevens, Basham, Lundstram, McBurnie (Mousset 80'), Sharp (McGoldrick 69'), Egan, Norwood, Robinson, Berge (L. Freeman 69').
Unused: Jagielka, K. Freeman, Osborn, Clarke, Moore, Rodwell.