Postpublished at 28 mins
Cardiff 0-1 Manchester City
Referee Lee Mason has just had to go over and speak with Pep Guardiola to confirm what happened then.
Meanwhile, Kevin de Bruyne takes another free-kick but it's off target.
Summary
De Bruyne with low free-kick under the wall
Unmarked Sterling with header for second
Cardiff's Bennett booked for tackles on Sane & Diaz
FT: Chelsea 3-0 Newcastle
Fifth-round draw in the One Show on BBC One on Monday - 19:00 GMT
Postpublished at 28 mins
'What a surprise'published at 16:28 Greenwich Mean Time 28 January 2018
Cardiff 0-1 Manchester City
Mark Lawrenson
BBC football expert on BBC OneMaybe the referee's assistant thought Leroy Sane maybe got a touch of the ball on the way through.
The day we want VAR we don't have it. What a surprise?
Are we saying Sane was in the line of the ball? You could have had six goalkeepers in there and they wouldn't have saved it.
Confusion!published at 27 mins
Cardiff 0-1 Manchester City
What happened there? Everybody was confused. Manchester City thought they had scored and so did we.
But it was ruled out because Leroy Sane was off-side when he was deemed to have interfered with play.
Image source, ReutersGoaa - Oh wait!published at 26 mins
Cardiff 0-1 Manchester City
Image source, ReutersKenneth Zohore looks to create an opening for Cardiff but his shot is blocked by Danilo.
Manchester City then break up the pitch in numbers and Bernardo Silva strikes it perfectly into the top right corner.
But it's not been given!
Postpublished at 16:26 Greenwich Mean Time 28 January 2018
Cardiff 0-1 Manchester City
Nathaniel Mendez-Laing down Cardiff's right has seen more ball than anyone in a blue shirt with 13 touches. As you can see, they are using that flank a lot.
Image source, .get involved Get Involvedpublished at 16:24 Greenwich Mean Time 28 January 2018
Tweet #bbcfootball or text 81111
Daniel: I’ve missed Claudio Bravo in the Premier League. Guaranteed goals when that guy is playing.
Harsh?
'Fantastic contest'published at 16:23 Greenwich Mean Time 28 January 2018
Cardiff 0-1 Manchester City
Steve Claridge
Ex-Premier League striker on BBC Radio 5 liveThis is shaping up to be a fantastic contest. Cardiff have had a really good chance to get level but Manchester City's counter is so quick and that will be a real concern. The home side will need to take risks if they are going to get back into this game, more risks than they would like, but it will make for a very good game.
Image source, ReutersPostpublished at 23 mins
Cardiff 0-1 Manchester City
Leroy Sane wins the ball back for Man City after some nice, neat play from Cardiff down the right-hand side.
Vincent Kompany is just trying to settle things down a bit now and keep possession. It's been very open in this game.
Postpublished at 21 mins
Cardiff 0-1 Manchester City
Ilkay Gundogan has been given so much space in these opening stages for Manchester City.
He drives through the middle but his shot is blocked before Cardiff recover.
CLOSE!published at 19 mins
Cardiff 0-1 Manchester City
Callum Paterson and Nathaniel Mendez-Laing were so close to getting on the end of a wicked cross but it misses them by inches.
There were no Manchester City defenders to be seen.
CLOSE!published at 18 mins
Cardiff 0-1 Manchester City
Cardiff come close again!
David Hoilett is involved as he turns sharply in the box. The ball bobbles around the six yard area and it's not properly cleared until Vincent Kompany sticks a leg out at it and boots it away.
CLOSE!published at 15 mins
Cardiff 0-1 Manchester City
Cardiff thought they had scored!
The ball almost rolled over the line following David Hoilett's strike but Claudio Bravo just about recovers it.
The crowd were half-celebrating.
Remember, there is no VAR today - but the goal decision system shows the ball did not cross the line.
Chumps...published at 16:16 Greenwich Mean Time 28 January 2018
Cardiff 0-1 Manchester City
An alternative viewpoint/analysis from Danny Baker...
This Twitter post cannot be displayed in your browser. Please enable Javascript or try a different browser.View original content on TwitterThe BBC is not responsible for the content of external sites.Skip twitter postThe BBC is not responsible for the content of external sites.Allow Twitter content?
This article contains content provided by Twitter. We ask for your permission before anything is loaded, as they may be using cookies and other technologies. You may want to read Twitter’s cookie policy, external and privacy policy, external before accepting. To view this content choose ‘accept and continue’.
End of twitter postApp users may need to click the link to see content.
Postpublished at 16:15 Greenwich Mean Time 28 January 2018
Cardiff 0-1 Manchester City
Dafydd Pritchard
BBC Sport Wales at the Cardiff City StadiumWell, that cheeky free-kick from De Bruyne has rather punctured the mood for the home fans at the Cardiff City Stadium.
It has been an enthusiastic start from the hosts, but perhaps too much so as Joe Ralls' lunge on Ilkay Gundogan proved costly, leading as it did to the free-kick.
Get Involvedpublished at 16:15 Greenwich Mean Time 28 January 2018
#bbcfacup or 81111 on text
Colin: The reaction of the Cardiff wall afterwards said it all. What a free-kick by De Bruyne!
Phil: Cheeky. Naughty. Delightful. Class from De Bruyne.
Steven: What a free-kick by De Bruyne! Whole wall fooled.
Robert: The cardiff goalkeeper might as well have been sat smoking a fag in the stands for all the good he did on that free-kick.
Postpublished at 14 mins
Cardiff 0-1 Manchester City
Cardiff had the ball but Marko Grujic held on to it for far too long. Danilo takes it off him and he is then flattened by Sean Morrison.
Literally, flattened.
De Bruyne's free-kick is blocked this time but Manchester City have a corner.
Image source, ReutersClap manpublished at 16:13 Greenwich Mean Time 28 January 2018
Cardiff 0-1 Manchester City
The clap emoji. Says it all from Southampton's Charlie Austin.
This Twitter post cannot be displayed in your browser. Please enable Javascript or try a different browser.View original content on TwitterThe BBC is not responsible for the content of external sites.Skip twitter postThe BBC is not responsible for the content of external sites.Allow Twitter content?
This article contains content provided by Twitter. We ask for your permission before anything is loaded, as they may be using cookies and other technologies. You may want to read Twitter’s cookie policy, external and privacy policy, external before accepting. To view this content choose ‘accept and continue’.
End of twitter postApp users may have to click on the link.
Postpublished at 12 mins
Cardiff 0-1 Manchester City
Kyle Walker has the ball in the Cardiff box and he has so much time, he practically walks the ball along the back-line before trying to pick out Raheem Sterling.
It's blocked and cleared but Man City have the ball again.
'Clever De Bruyne'published at 16:12 Greenwich Mean Time 28 January 2018
Cardiff 0-1 Manchester City
Steve Claridge
Ex-Premier League striker on BBC Radio 5 liveDe Bruyne is a clever footballer, the way he plays the game and the way he thinks about the game, the passes he makes and his vision, but what he has done there is just fantastic.
They don't need to jump, if he gets it up and over then you hold your hands up and say well done but he's just rolled that into the corner.
They need to make sure they stay in this game now Cardiff.
Image source, ReutersPostpublished at 11 mins
Cardiff 0-1 Manchester City
We have got a real cup tie on our hands now. Cardiff have to go for this. So far, they haven't really got going and Manchester City have already shown their class.