Use audio icons at top of page to listen to BBC radio commentaries
FT: Nottingham Forest 1-1 Bristol City - Origi opens scoring & Knight levels, before hosts win 5-3 on penalties
Forest will now host Man Utd
FT: Aston Villa 1-3 Chelsea - Gallagher opens scoring & Jackson doubles lead before superb Fernandez free-kick; Diaby pulls one back
Chelsea will host Leeds United next
Get Involved: #bbcfootball, WhatsApp on 03301231826 or text 81111 (UK only, standard message rates apply)
Enzo Fernandez
That's a MAGNIFICENT goal!
World Cup winner Enzo Fernandez beats World Cup-winning keeper Emi Martinez with an outstanding free-kick.
The set-piece is about 25 yards out but Fernandez shows brilliant skill to bend it beyond his Argentina team-mate.
Image source, ReutersAston Villa 0-2 Chelsea
Dion Dublin
Former England striker on BBC Radio 5 Live
Fernandez and Caicedo are doing it so well that they are almost on the toes of their centre-halves so there aren't any gaps for Villa to get through them.
Then when they win the ball, one of them goes and the other stays.
Nottingham Forest 1-1 Bristol City
Forest, who are at home to Newcastle on Saturday, could do without extra-time.
Nuno Espirito Santo has sent on Callum Hudson-Odoi and Taiwo Awoniyi in an attempt to win this in 90 minutes.
#bbcfootball, text 81111 (UK only - standard rates apply) or WhatsApp 03301231826
If this Chelsea turn up against the Liverpool side who played Arsenal at the weekend, the Carabao Cup final might actually end up being a bit of a contest.
Alex
Aston Villa 0-2 Chelsea
Phil McNulty
BBC Sport chief football writer at Villa Park
Lots of sentences starting with the words “if Villa get an early one in the second half…” during the break but they will have to play a lot better to get one.
Chelsea have been first to everything and Villa have just given the ball away too often.
Aston Villa 0-2 Chelsea
Do Chelsea stick bodies behind the ball or go for a third goal?
The start of the second half has been peppered by fouls. That will suit the visitors.
Aston Villa 0-2 Chelsea
Cole Palmer gets the second half started.
HT: Aston Villa 0-2 Chelsea
What has Unai Emery said to his players? Villa need an early second half goal.
The teams are on their way out.
Image source, Getty ImagesNottingham Forest 1-1 Bristol City
Corner to Bristol City. Matt Turner comes out to clear and misses it but the visitors cannot take advantage.
#bbcfootball, text 81111 (UK only - standard rates apply) or WhatsApp 03301231826
Gareth: Is it any coincidence that the absence of the grumpy, (potentially self-entitled), elder statesmen of the squad - Thiago Silva and Raheem Sterling - is empowering the other (younger) players - who are also largely being picked in their favoured positions for once - to go out and perform? Just saying…
Anon: Dare I say that Chelsea are playing better because Thiago Silva isn't in the side?
Elliott: There's something more than a little bit ironic in Thiago Silva being dropped and Chelsea playing well tonight.
HT: Aston Villa 0-2 Chelsea
Rob Green
Former England goalkeeper on BBC Radio 5 Live
The togetherness is there, the togetherness as a unit is there.
Chelsea have performed for 45 minutes and got it right.
Conor Gallagher took his goal brilliantly and the confidence grew from there. They did it to a tee.
Image source, Getty Images#bbcfootball, text 81111 (UK only - standard rates apply) or WhatsApp 03301231826
Ryan: When will Madueke be given a run of games?!?! Aggression and guile. Like a mini Rudiger!
Jam: I'm just happy this is being described as a massive upset. That's extraordinary in itself.
HT: Aston Villa 0-2 Chelsea
Dion Dublin
Former England striker on BBC Radio 5 Live
Nicolas Jackson has been excellent up front and the defence has been great. As for Villa, I don't know where they are.
Chelsea have been brilliant.
Nottingham Forest 1-1 Bristol City
Wave after wave of attacks from Bristol City. The ball is pinging around inside the Forest box. The home team have struggled to get out of their own half since the start of the second half.
HT: Aston Villa 0-2 Chelsea
Rob Green
Former England goalkeeper on BBC Radio 5 Live
It's a performance where the Chelsea fanbase can say 'we can buy into this'.
It wasn't all that fast actually, but the confidence and the direction they had, it felt like something that hasn't been there in recent weeks.
You can see what this team is about and we haven't seen that.
Image source, Getty ImagesNottingham Forest 1-1 Bristol City
Another big chance for the visitors but Matt Turner is equal to Anis Mehmeti's attempt.
That was Bristol City's sixth attempt on target.
HT: Aston Villa 0-2 Chelsea
Rob Green
Former England goalkeeper on BBC Radio 5 Live
I think it was really interesting that Villa started quick and they were turning Chelsea.
Just before the goal, Unai Emery turned to his team and asked them to play football. They got caught on the ball and Chelsea went on the attack and all of a sudden they were ahead.
They had that energy and dynamism and really tore Villa apart at times.
Image source, Getty ImagesNottingham Forest 1-1 Bristol City
The FA Cup does funny things to teams. Bristol City are in the bottom half of the Championship yet they are giving their Premier League hosts the runaround.
A lively start to the second half almost results in Jason Knight carving out a great chance.
HT: Aston Villa 0-2 Chelsea
Dion Dublin
Former England striker on BBC Radio 5 Live
Chelsea started really poorly and Villa came out great.
But after about five or 10 minutes, Chelsea took control and they have dictated play. The defence has been very good too.
Nottingham Forest 1-1 Bristol City
Who will be playing Manchester United in the next round?
Bristol City get the second half rolling.