Simon Stone
BBC Sport at the Etihad Stadium

Pep Guardiola is mystified why Manchester City didn't get a penalty then.

A clearly agitated City boss had a long conversation with fourth official Jonathan Moss to express his displeasure, then started waving his arms at Moss after Kevin de Bruyne had been fouled.

Pep not happy. One to keep an eye on if City don't equalise.

Sane has acres of space to run in to after beating a Town man in his own half. He has two players with him but a poor touch allows an away defender to nick the ball. He should have played Aguero in.

The away fans are happy - and deservedly so.

Image source, Rex Features

But Pep isn't as impressed...

Image source, Getty Images

Simon Stone
BBC Sport at the Etihad Stadium

I just had a message from a Huddersfield supporting friend to say the last time they wore a strange kit against Manchester City, they lost 10-1 (November 1987).

There's the 1.

City fans sat near to the press box not impressed by the goalkeeping.

Before Huddersfield went in front, Leroy Sane was a whisker from giving Man City the lead. Watch him hit the post here.

Pat Nevin
Ex-Chelsea winger on BBC Radio 5 live

I can't see Huddersfield lasting the whole game without conceding a goal. The quality of chances and the porousness of that defence, you see City breaking through at some point.

Watch as former Man City academy player Harry Bunn gives Huddersfield the lead. 

City are pounding on the door. Raheem Sterlking breaks into the box and pulls the ball back for Fernandinho, whose goal-bound shot is deflected over by another Town arm.

No penalty says the ref. From the corner, Nicolas Otamendi heads over.

No surprise to see Pep Guardiola having a little word with the fourth official. They are feeling a bit hard done by.

Danny Murphy
Former England midfielder on BBC One

For me it is a penalty. He is about to put into an empty net. The defender is on the floor, his arm is outstretched. It is preventing a goal. Penalty.

Huge calls for a handball against the visitors. Ref says no. It was, though. It is a suicidal pass from Tareiq Holmes-Dennis that sets City up on the attack. Kevin de Bruyne carries the ball into the box and cuts back inside before playing a low ball that a Jon Gorenc Stankovic deflects away from what would be a simple finish with his arm.

Image source, Rex Features

Kevin de Bruyne fires the free-kick over the wall and on target but the Town keeper gathers after initially spilling the shot.

Image source, AFP

Sergio Aguero is held up by Mark Hudson as he tries to collect a return pass from Raheem Sterling. It is a dangerous free-kick near the Town box and a booking for Hudson.

Image source, AFP

Playing FA Cup bingo? Here's a foil cup for you. The Huddersfield fans are loving life at the moment.

Image source, Getty Images

That goal has stunned City a bit. They're the Premier League team. They've gone near full strength. Huddersfield are weakened. How can this happen?!

Danny Murphy
Former England midfielder on BBC One

Incredible. City should be 1-0 up and then Huddersfield score. 

Philip Billing has started this game brilliantly and it is his touch which sets up the goal - great awareness, great weight. 

It is a good counter by Huddersfield.

City won't panic. They need to keep passing the ball to players who will create and cause problems for Huddersfield .

Pat Nevin
Ex-Chelsea winger on BBC Radio 5 live

Game on. What a brilliant break there. Philip Billing just cruised away from the rest of the midfield and played the ball to Harry Bunn, who had plenty of time. What a good decision to bring him into the team from the manager.

If you ask goalkeepers, the ones they hate are the low ones drilled from close range. That's what he got there.

I know Huddersfield made a lot of changes but I don't see it as a weakened team.

The apple cart is upset! Huddersfield lead! Town break with purpose down the left and Philip Billings' neat pass sets up Harry Bunn - who came through the ranks at City - to fire low under Claudio Bravo. Now we have a game on our hands.

Image source, Rex Features

City are warming to the task. Sergio Aguero slices right through the Town defence before firing a low shot from an angle that is saved by Joel Coleman.

Danny Murphy
Former England midfielder at the Etihad Stadium

It was a brilliant strike from Sane. It came from the danger down the sides. Sane has been brilliant in recent weeks, he is starting to show the talent and ability he has got.