Willian comes on for Pedro. Chelsea have a mountain to climb at Wembley.

Jermaine Jenas
Former England midfielder on BBC Radio 5 live

Arsenal have to use their brains now, they need to keep the ball in the attacking areas and make Chelsea work even harder.

Anthony Taylor is not scared of making the big decisions in the big games, is he?

I'm sure you're all keen to give us your opinions on that via #bbcfacup...

Image source, Reuters

Danny Murphy
Former England midfielder on BBC One

He didn't argue did he. I don't know what he is thinking.

It's a great example of why you shouldn't do it.

This has given Arsenal even more of an opportunity.

Jermaine Jenas
Former England midfielder on BBC Radio 5 live

It is a brilliant decision from referee Anthony Taylor, he has a good long, look at it and he has a great view.

Victor Moses dives, he cannot complain. No Chelsea player can complain.

Image source, Reuters

Dive, says referee Anthony Taylor!

A second yellow card in 13 minutes for Victor Moses. He's off and Chelsea are down to 10!

Moses goes down while in close proximity to Nacho Monreal. There did not seem to be much contact, but Moses hardly went flying down.

Victor Moses goes down in the box under pressure from Alex Oxlade-Chamberlain.

A penalty or a dive?

A great stop from Thibaut Courtois, after a blistering Arsenal attack.

Danny Welbeck side-foots for Mesut Ozil, who's steaming through the middle, but the ball falls to Hector Bellerin and the full-back's low drive is saved.

This is still so open. You just don't know which way the pendulum is going to swing next.

Mesut Ozil tries to play through an on-rushing Danny Welbeck but he can't get the angle right.

Cesc Fabregas has been directly involved in six goals in his last six games before today (one goal and five assists).

Image source, Reuters

Danny Murphy
Former England midfielder on BBC One

You expected Chelsea to come back after half time and up the tempo.

Now Fabregas has come on, you will notice Diego Costa's runs will change because he knows he can find him.

Jermaine Jenas
Former England midfielder on BBC Radio 5 live

This is a big moment, Cesc Fabregas has been itching to come on. He has been rallying the troops from the sidelines and now he has the chance to impact the game against his old side.

Image source, Getty Images

First switch to Chelsea.

Cesc Fabregas, former Arsenal man of course, comes on in a like-for-like swap with Nemanja Matic.

Fabregas has sparkled in his last few games - particularly against Middlesbrough. He might be what Chelsea need right now...

How is this game changing? Chelsea's first-half possession was 44.9% - so far in the second half it is 69.9%.

Image source, PA

Danny Murphy
Former England midfielder on BBC One

Sanchez has been the best player on the pitch by a mile but the rest of the Arsenal players are trying to catch him up with their performances.

But the longer the game goes, on this pitch, you have got to conserve a little bit of energy.

Victor Moses finds Pedro in space.

The Chelsea attacker goes from distance and his effort spins wide of the target.

Ay up, another yellow card now. N'Golo Kante goes in the book for blocking Aaron Ramsey.

And still Chelsea keep coming....

Rob Holding has to head clear from a dangerous Chelsea ball into the box. The resulting corner comes to nothing.

Now Danny Welbeck is brought down by Victor Moses and the latter receives a yellow card.

This game has bite.

Danny Murphy
Former England midfielder on BBC One

It's a brilliant block but it's a bad ball from Bellerín. He has lifted it - just roll it!

Phil McNulty
BBC Sport chief football writer at Wembley

Chelsea have finally arrived at this FA Cup final - and defender David Luiz has just prepared for a free-kick by waving his arms to demand more noise from their fans. The response was instant and deafening.