Postpublished at 22:10 Greenwich Mean Time 16 December 2014
That's a wrap from tonight's League Cup action then. Join us tomorrow night for the second half of our quarter-final midweek session. See you there.
Derby's Buxton sent off for foul on Remy
Chelsea defender Zouma suffers head injury
Result: Sheff Utd 1-0 Southampton
Gardos sent off for Southampton late on
Watch Final Score by using play button
Tom Rostance
That's a wrap from tonight's League Cup action then. Join us tomorrow night for the second half of our quarter-final midweek session. See you there.
That's five defeats in a row for Southampton. A few of you are saying that the side look tired. Time for some January shopping?
Tom from Sheffield: The Blades have now made five semi finals in the major cups in 16 years, that's almost one every three years for a team that's spent a single season in the top flight.
Chelsea boss Jose Mourinho: "Derby are a Championship side but not a typical one, they have more quality than that and they play good football with fantastic support.
"We played in a very professional way and controlled the game for most of the time. They fought to the end and for a few minutes after they scored they were able to put us in trouble.
"Cesc Fabregas is playing so well for us. What I like is as a person he is a professional. He is a World Champion, he comes here to play in the Capital One Cup and plays like that, That is the character I like."
Conor McNamara
BBC commentator
"Sheffield United absolutely deserve their win. They rolled up their sleeves and they just wanted it more. It's not like Southampton didn't turn up wanting to win but there seemed to be no determination, no dedication. Sheffield United had 11 heroes out there and it's yet another scalp for Nigel Clough.
"17-year-old Louis Reed ran the show in the middle of the park, Kieran Wallace came on as his replacement, he's only 19, and they had 18-year-old Che Adams playing as well. Clough has been rewarded on a night he put his faith in youth."
Rian Hoskins:, external Excellent by Sheffield United but Southampton have missed their best opportunity to qualify for Europe. The squad looks tired.
Chelsea midfielder Cesc Fabregas: "These kinds of games are always difficult. It is probably their biggest game of the season and we have to be up for it.
"I'm enjoying playing in this team, we have a very strong squad and we want to go for everything. We can get better, 100% and we know that. Everyone is really focussed and professional but the next two or three weeks are very important.
"Time will tell how good this season can be. We have the talent, the discipline and the courage to do it, I know that."
We now know two of the last four sides in the League Cup - here's a reminder.
Chelsea are through after beating Derby.
Sheffield United are through after beating Southampton.
Tottenham v Newcastle (19:45 GMT on Wednesday)
Bournemouth v Liverpool (19:45 GMT on Wednesday)
Conor McNamara
BBC commentator
"Nigel Clough has been in charge of 18 cup games as Sheffield United manager. He's only lost two of them. Dad would be proud."
Back to the Championship slog for Derby then, who are well in the mix for a promotion back to the top flight. Is Steve McClaren on the verge of becoming a Premier League manager once more?
Chelsea join the Blades in the last four. A comfortable enough win for Chelsea in the end but the game was slightly marred by that red card for Jake Buxton. Chelsea have injuries to Didier Drogba and Kurt Zouma to worry about too.
A fantastic win for Sheffield United, who will learn their semi-final opponents tomorrow night.
BBC Radio 5 live sports extra
Former Southampton striker Kevin Phillips: "Sheffield United were brilliant. I could have given 11 man of the matches tonight but Marc McNulty for me was brilliant. Sheffield United had desire, commitment and work rate. They have shown what they can do against Premier League teams over the last two seasons and that is if you do not turn up here, you get beaten."
All over and Sheffield United are into the League Cup semi-finals! Another Premier League scalp for Nigel Clough.
THREE MINUTES added on. Chelsea are going through but with injuries to Kurt Zouma and Didier Drogba.
Chelsea cruising now, with just three minutes to go.
Ben Goodwin:, external Absolutely no way Remy was going to get to that, Derby have just been completely robbed. Chelsea getting the decision as always.
Oh dear! This does not look like it will be Southampton's night as they are reduced to 10 men, frustration bubbles over, Florin Gardos fouls Marc McNulty and is shown a red card.
Four minutes of injury time.
The iPro crowd are not happy with the way this game has gone. It was a soft red card which swung the momentum back the way of Chelsea.
Ramires replaces the excellent Eden Hazard, while Derby throw on Leon Best. Seven minutes left.
Clinical stuff from Chelsea as they capitalise on the extra man. Cesc Fabregas picks out Loic Remy on the right of the box, his shot is parried out by Lee Grant and Andre Schurrle reacts first to slam into the net from eight yards out. Game over, Chelsea into the last four.