QF draw: Man Utd v Brighton, Leicester v Chelsea
Sheff W/Swansea v Rochdale/Tottenham, Wigan/Man C v Southampton
Lukaku scores goal in each half for United
Mata strike ruled out by VAR for offside
Huddersfield 0-1 Man Utd
60% of Huddersfield's play has come from down the right-hand side.
Danish midfielder Philip Billing looks to take matters into his own hands, but his swinging left-footed curler from out wide is comfortable for Sergio Romero to deal with.
A little more trajectory and the United goalkeeper would have been in trouble.
Huddersfield 0-1 Man Utd
Steve McClaren
Ex-England manager on BBC Radio 5 live
Manchester United just strung about 12 passes together for the first time in the game.
But there is just no intensity. It is so easy for Huddersfield to get the ball back.
Huddersfield 0-1 Man Utd
Image source, .Manchester United only have two players spending most of their time in the Huddersfield half (graphic on the right), with Juan Mata their most advanced player.
Compare that to Huddersfield, who are playing very high up the pitch indeed (left graphic).
Huddersfield 0-1 Man Utd
Deary me, United defenders Chris Smalling and Victor Lindelof are an accident waiting to happen.
No communication between the two, the pair go for the same high ball into the box and nearly end up knocking each other out.
No harm done though.
Huddersfield 0-1 Man Utd
United are trying to get the ball down and control possession, but are being given no time at all by the Terriers, who are biting at their ankles straight away.
Is it fair to say it is a dogged performance or am I barking up the wrong tree?
Image source, AFPHuddersfield 0-1 Man Utd
Danny Williams with a low drive for the hosts from 30-odd yards out, straight down the throat of goalkeeper Sergio Romero.
Huddersfield 0-1 Man Utd
Juan Mata has provided 28 assists for Manchester United since his debut, more than any other player at the club.
His team, though, are lucky to still be leading.
It is all Huddersfield.
Image source, ReutersHuddersfield 0-1 Man Utd
Steve McClaren
Ex-England manager on BBC Radio 5 live
Manchester United are allowing Huddersfield to run at them.
If they are pressed, they make mistakes but United have not put any pressure on. I expected United to push on after the goal but they haven't.
Huddersfield really deserve something so far in this game.
Huddersfield 0-1 Man Utd
Huddersfield thumping on the door like an angry gas man desperate to read the meter, but United are keeping them out...for now.
Huddersfield 0-1 Man Utd
Image source, .Huddersfield dominating possession but Manchester United have what matters at the moment - a goal.
Huddersfield 0-1 Man Utd
Huddersfield are giving United full-back Luke Shaw a torrid evening so far, all their play is coming down that side.
Danny Williams clips a cross to the back post for Rajiv van La Parra, whose header is straight at Sergio Romero.
The Terriers go again, this time courtesy of Florent Hadergjonaj, who plays in a fantastic defence-splitting ball into the box, but Tom Ince cannot get sufficient contact on the ball to convert.
Huddersfield 0-1 Man Utd
Alistair Yeomans
BBC Radio 5 live at Huddersfield
Good comeback this by Huddersfield and Mourinho cuts an agitated figure even though United lead. He keeps looking back into the dug out to talk to his assistants.
Image source, Reuters#bbcFACup or text 81111 (UK only)
Smalling bats a corner with his hand. If only we had VAR, oh, wait...
Marlo, London
Blatant handball by Smalling, but not according to VAR. Absolute joke, it's never gonna work if they bottle it every time it goes against a big club.
Dave, Manchester
Huddersfield 0-1 Man Utd
It is Huddersfield who are now being forced to work at the back.
The hosts give the ball away and Romelu Lukaku plays it through to Alexis Sanchez, but the Chilean cannot find a team-mate with his cutback.
It has been a superb opening 20 minutes to this game, but how long can the break-neck pace continue for?
Image source, PAHuddersfield 0-1 Man Utd
Steve McClaren
Ex-England manager on BBC Radio 5 live
Manchester United just can't get six passes together.
They need to start to control the game but Huddersfield are just not letting them.
But for all the attacking Huddersfield have done, every time United get the ball, you just think they are going to score.
Huddersfield 0-1 Man Utd
United seemed to have weathered that Huddersfield storm and go on the attack for the first time since the goal.
Home defender Christophe Schindler sticks a foot out to Ashley Young's low cross and diverts it away from goal.
That could easily have flown in.
Huddersfield 0-1 Man Utd
Romelu Lukaku finishes at the near post after being put through by Juan Mata, to the delight of the travelling supporters.
Huddersfield 0-1 Man Utd
Steve McClaren
Ex-England manager on BBC Radio 5 live
Hadergjonaj is over-running Sanchez for fun.
United need to get the ball more to Sanchez.
Huddersfield are pressing intensely so that United give the ball away.
They've had four corners already in the opening 10 minutes.
Huddersfield 0-1 Man Utd
And still Huddersfield apply the pressure.
They are taking aim from down the right, and Sergio Romero has to deal with a dangerous cross into the box by Colin Quaner, tipping the ball over the crossbar.
Image source, ReutersHuddersfield 0-1 Man Utd
Despite going behind, the Huddersfield supporter are still making a big noise. They can probably be heard over in Leeds.
"Stand up if you love the town," they sing.
Florent Hadergjonaj has a crack from the edge of the box, but United goalkeeper Sergio Romero gathers it easily.