It was a result that few would have seen coming, least of all Huddersfield Town.
The Terriers registered their first win over Manchester United in 52 years at the John Smith's Stadium, triumphing 2-1 thanks to Aaron Mooy and Laurent Delpoitre's first half strikes.
Marcus Rashford pulled one back for United, but they were unable to turn things around against David Wagner's men, who held on for a famous victory in their first ever Premier League season.
With Manchester City beating Burnley 3-0 at the Etihad Stadium, it meant that United slipped five points behind their now not-so near neighbours on a miserable day for them .
And here are some stats they'd rather forget.
United had 78 per cent possession during the match, but only registered three shots on target, the same as Huddersfield
And if you're good at maths you'll realise that that means the Terriers had just 22 per cent of the ball, but managed to register the same amount of efforts at goal as their opponents.
Two of them went in, of course.
The two hardest working players on the pitch were both in blue and white stripes
He didn't just score Huddersfield's opener on the day, Aussie international Mooy was also the hardest working player on the pitch.
Mooy ran 13km during his 90 minute display, pipping his teammate Jonathan Hogg (12.6km) to the marathon man of the day award, with only Nemanja Matic (12.2km) outrunning a third Huddersfield player, the midfielder Danny Williams (12.1km).
After coming on for the injured Phil Jones, Victor Lindelof's first half was the stuff of nightmares
He's hardly the most popular figure among United fans already, but £31m Swedish defender Lindelof's calamitous introduction really was shocking.
Within 10 minutes of his arrival, United had conceded the same amount of goals as they had in their previous eight Premier League games, with his error allowing Delpoitre in for Huddersfield's second.
Jose Mourinho is not a manager who can mastermind a Premier League comeback
When a Jose Mourinho side goes two goals down in the Premier League, they might as well pack up and go home.
On the 19 occasions it has now happened, Mourinho's teams have lost 18 and drawn one, perhaps indicating that he isn't a manager capable of radically altering his approach and chasing a game when caution needs to be thrown to the wind.
Romelu Lukaku has now gone three games without a goal
Alright, it's only three games, but at the elite level Romelu Lukaku operates at then that is still a slight cause for concern following his stunning start to the season.
Below-par performances against Liverpool, Benfica and now Huddersfield aren't what United shelled out £75m for, and the Belgian looks like he needs a rest - which he can get in the Carabao Cup fixture against Swansea - before next week's visit of Tottenham.