Martin Keown
Former Arsenal defender on BBC One

There is definite contact. Herrera knows exactly what he is doing. Hazard is the danger man for sure. He is like a slalom skier on the move.

United may have started on the front foot but they are being battered backwards at a rate of knots now. Eden Hazard is checked by Ander Herrera, who is perhaps a bit unlucky to be booked.

Herrera surrounds and berates referee Michael Oliver like a peak Roy Keane.

Image source, AP

Press high, press hard. That was the gist of Jose Mourinho's team-talk. Manchester United's tactics have been clear to see, perfectly illustrated by our average position graphic.

United players, on the right, have been on the front foot, trying to pin back their Chelsea opponents. And that they have managed to do, apart from the flurry of Blues attacks a moment or two ago.

Image source, #bbcfacup

Martin Keown
Former Arsenal defender on BBC One

What a save it is from De Gea. It was as if time stood still. It is going to take something special to beat the United keeper tonight.

A superb set of saves from David de Gea keeps Manchester United on level terms. If you saw Real Madrid keeper Keylor Navas have a nightmare last night you'll understand why the rumours keep on coming...

Jermaine Jenas
Former England midfielder on BBC Radio 5 live

Wow. That's all you can say about Eden Hazard there. He knew Chris Smalling would try to get tight and the turn to get away from him was sensational.

This is some serious defending from Manchester United now.

And again! That's an even better save as David de Gea somehow claws out Gary Cahill's low shot from the corner.

How did he stop that?!

Martin Keown
Former Arsenal defender on BBC One

Phil Jones has been assigned to Hazard but the Manchester United defenders are very tuned in to when he sets off on one of those driving runs. He is a special player.

He comes alive and gets away with a little turn. He really is a box of tricks.

That is brilliant! Eden Hazard spins away from Chris Smalling on the halfway line, and the alarm bells are clanging in the United defence.

Hazard runs on, skipping past one, two more and then hitting a low shot which is pushed clear.

Image source, AP

Matteo Darmian is a lucky boy not to be booked for that, a rash sliding challenge through the back of Willian. Referee Michael Oliver suggests that is his final chance.

David Luiz lines up a 35-yard free-kick but they play it short and the move comes to an end as Ashley Young launches into a tackle. 

Martin Keown
Former Arsenal defender on BBC One

It is good play from United. Rashford with that pace. Mkhitaryan has ability with both feet but he just hits the shot wide.

David Luiz has a lookalike in the crowd...

First shot of the night! Marcus Rashford stretches the play with his pace to chase a ball down the sides, he lays the ball off to Armenian trickster Henrikh Mkhitaryan on the edge of the box.

Paul Pogba is making ground to his left but Mkhitaryan shoots low, hard - and wide!

Good effort.

Jermaine Jenas
Former England midfielder on BBC Radio 5 live

Manchester United made a huge change in their tactics but they seem to have adapted to it very well.

Chelsea are getting frustrated already. They are getting pressed in areas of the pitch where they are not usually put under pressure.

Martin Keown
Former Arsenal defender on BBC One

It is an interesting move putting Phil Jones in that midfield position. He was talked about as the next Duncan Edwards when he first moved to United. Does he have the ability to play in there?

The first 10 minutes have absolutely trundled by. It's been a lot of tackles and first-time passes out of play. Not a classic. 

Matteo Darmian takes Eden Hazard down on halfway, Chelsea can't get into the Manchester United half so far. Stopped by fair means or foul.

High pressure, high pressing start from Manchester United, as they force Gary Cahill into an error. Phil Jones then gets the better of N'Golo Kante.

Jones could play his way into Gareth Southgate's England midfield tonight. No, seriously, he could.

With Eric Dier playing in defence and everyone else injured, there aren't many other options. Even Harry Winks is (allegedly) being courted by Spain...

Phil McNulty
BBC Sport chief football writer at Stamford Bridge

Jose Mourinho is pacing his technical area and clapping furiously in the direction of his Manchester United players already. The body language suggests this match back at the club where he enjoyed so much success means an awful lot to him.

It's almost worth bringing Martin Keown out of retirement like George Foreman to play for 90 minutes against Diego Costa.

Manchester United seeing plenty of early possession as Costa lands a challenge on Ander Herrera on halfway.