Manchester United had the chance to go top of the table but buckled under pressure against Sheffield who defeat the Red Devils 2-1 after one victory in Premier League this season.
Ole Gunnar Solskjær side have dragged themselves into a surprise title challenge, with this their first defeat in 13 games since they lost at Old Trafford against Arsenal in November.
Sheffield United victory is the first since 1973 that they will beat United at Old Trafford as the home needed three points to regain top spot from rivals Manchester City/
Kean Bryan headed home the opener after taking advantage of an error from David de Gea but former Sheffield United man, Harry Maguire scored his first goal at Old Trafford to level it up.
Maguire’s leveller came in the second half as United brought in Luke Shaw, and Edison Cavani to provide more attacking options but Sheffield manager, Chris Wilder’s substitute, Oliver Burke, paid off as he struck the winner via a big deflection off Axel Tuanzebe.
The result now leaves United in second spot, a point behind table topping Manchester City, who have a game in hand.
And this damaging result will be a reality check for Solskjaer and his team, who were desperately poor throughout and failed to exert any real pressure on the Sheffield United backline
However, New Chelsea manager, Thomas Tuchel, on Wednesday night failed to win his first game in charge of the club as the blue played a 0-0 draw against Wolves in the Premier League at Stamford Bridge.
Though Chelsea dominated possession and had 14 shots but failed to find the back of the net against Wolves.
The former Psg manager will now hope to win his first game for Chelsea when they face Burnley on Sunday in their next fixture.