It was a very hard day for Manchester United on Saturday afternoon as the Red Devils slumped to their first defeat of the season.Jose Mourinho's side made the short trip to Huddersfield for what was expected to be a routine three points, but they were defeated 2-1 by David Wagner's determined Terriers.Aaron Mooy opened the scoring, before Laurent Depoitre capitalised on a dreadful error from summer signing Victor Lindelof, who had replaced the injured Phil Jones.Marcus Rashford pulled one back from a brilliant Romelu Lukaku cross but in the end, United just didn't have enough to get even a point.It is a dark day for Mourinho's men who have endured a tough week and a number of big injuries.Marouane Fellaini and Paul Pogba have been huge misses in the heart of midfield, with Ander Herrera being singled out for a lot of abuse from United fans for his recent poor displays.Fellaini has evolved into a key player at United following his 2013 move from Everton, but one of his recent tweets will certainly come back to haunt him.Following their 4-0 win over Crystal Palace just before the international break, the big Belgian midfielder posted this rather prematurely.

FELLAINI'S TWEET

Unbeaten all season? Yeah, maybe not.

A few on Twitter had been speculating whether United could emulate the Arsenal 'Invincibles' from 2003/04, with one supporter posting yet another foolish tweet the day before the game.

UNITED FAN JOINS IN

Twitter is a brutal place.

The result at the John Smiths stadium effectively hands their bitter rivals Manchester City a huge advantage in the title race.

Pep Guardiola's free-scoring side brushed aside Burnley at the Etihad 3-0, to move five points clear at the top of the Premier League table.

United face a difficult game next weekend at home to Tottenham, while City make a much more favourable trip to West Brom.

The title race could already be over.