Our FA Cup dream is over for another year after a disappointing home defeat.
We were always up against it after conceding twice in the space of two first-half minutes, but it looked like we would mount a comeback once Pierre-Emerick Aubameyang tapped in just before half-time.
But injuries to both of our starting centre backs disrupted our rhythm and United sealed the win late on with another goal on the counter attack.
There was little between the sides in the opening half hour. We started well enough, enjoying plenty of possession if not able to create any clear-cut chances.
Unai Emery was forced into his first change inside 20 minutes when Sokratis limped off. Shkodran Mustafi came on to replace him in a like-for-like change in the back four.
Both sides were still feeling each other out, though neither were holding back in the challenge.
Then two goals in the space of two and a half minutes changed the whole complexion of the match.
First Alexis – on his first return to Emirates Stadium since joining United 12 months ago – ran onto a Romelu Lukaka pass, rounded Petr Cech, then converted from a narrow angle.
It got worse a matter of seconds later. Shortly after conceding, we were far too open at the back, United outnumbered us on the break and Jesse Lingard stroked home into the bottom corner.
It certainly knocked the stuffing out of us. We needed a quick response. Crucially we got it before the interval.
A flowing move finished with Aaron Ramsey putting in a low ball across the face of goal. Lacazette could only get a toe to it, but Aubameyang was on hand to tap in at the far post. Game on.
New life was breathed into the team. We ended the half on a high – Mustafi headed a decent chance just wide – and continued the momentum after the break. Ramsey had a header clawed just over the bar with the game opening up.
Both sides were looking dangerous going forward, the game developing nicely into a pulsating cup tie.
A lengthy stoppage to treat a facial injury to Laurent Koscielny threatened to halt the flow of the game.
Koscielny's withdrawal led to another change at the back - Xhaka dropped back while Mesut Ozil was also introduced into the action.
Ramsey had a shot wide, while Lacazette saw a fierce effort parried. We were committing men forward, and paid the price when United scored the third.
Paul Pogba strode through the midfield, fired in a shot which Cech could only turn into Anthony Martial's path, for a simple finish.
Despite a hefty chunk of time added on for Koscielny's injury, we were unable to claw our way back into the game, and exited the competition.
HOW IT HAPPENED
Click here for a play by play summary of our FA Cup fourth round defeat.
WHAT IT MEANS
Our FA Cup hopes are over for another year, and we won't be extending our record-breaking haul of 13 cups this season. It's now full focus on the Premier League until the Europa League resumes in February.
We return to Premier League action this Tuesday night with a home game against Cardiff City. The match kicks off at 7.45pm as we look to put pressure on Chelsea in fourth place, who play the following night.
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