Manchester United suffered a shock 2-1 home defeat by the Premier League's bottom club Sheffield United on Wednesday to leave Manchester City alone at the top of the table.
Substitute Oliver Burke grabbed the 74th-minute winner after Harry Maguire had cancelled out Kean Bryan's first-half opener for the Yorkshire side who had won just one league game all season before their trip to Old Trafford.
City are top on 41 points, a point ahead of United who have played one game more.
Sheffield United went ahead in the 23rd minute when Bryan headed in John Fleck's corner with United keeper David De Gea flapping at the cross, although replays suggested he may have been pushed by Sheffield striker Billy Sharp.
United's frustration over that decision was amplified when Anthony Martial had the ball in the net but the effort was ruled out for a foul by Harry Maguire on keeper Aaron Ramsdale.
Ole Gunnar Solskjaer's side were lacking any of the zip and invention of their recent good run of form but managed to get on level terms when their Sheffield born captain Harry Maguire met an Alex Telles corner with an unstoppable header.
United paid the price from hesitant defending, however, when Burke's low drive deflected off Axel Tuanzebe and crashed in off the underside of the crossbar.
