A powerful second-half showing from Chelsea saw Southampton concede three goals in the Premier League for the first time this season. Saints were gifted the lead after just 12 second when Michael Essien's woeful backpass let in Jay Rodriguez and they were good value for that lead at the break. But Chelsea moved through the gears in the second period with goal from Gary Cahil, John Terry in his 400th Premier League game and Demba Ba taking them up into second spot in the table.
Saints force a corner that Osvaldo plays short but then loses it to Ivanovic with a sea of red shirts waiting for a cross.
We will have a minimum of six minutes added time.
It's the first time Southampton have conceded three goals in the Premier League this season and you just would not have predicted it would happen at half-time when they were leading and so much in control.
Ramires gets in a cross that is met first time by Ba as he slides in and the ball finds the corner of the net.
GOAL! - Ba makes it 3-1 for Chelsea.
Some fans are heading for the exits which will let the players know there is not long to go so will be there be late drama?
Osvaldo tries a shot which loops just wide of Cech's goal and the home keeper dod not look too confident with that.
Ba is caught offside and after so many of them in the opening 45 minutes, I think this is the first one of the second period!
A bit of a lull in play which is surprising with only one goal between the sides.
Osvaldo is booked for a foul on Mata.
Chelsea bring on John Obi Mikel for the hard-working Torres.
Gazzaniga races off his line to gather the ball ahead of Ba after Mata's pass threatened to put him clear.
Just a warning for the home side that their job is still not done.
Cech then does well to claim the ball ahead of Lambert after Shaw had put in a decent cross.
Osvaldo leads a rare Saints attack and lays it off to Lambert on the edge of the box, but Cahill blocks his shot and Rodrirguez loses the ball to Lampard.
The hosts are looking for a third and again keeper Gazzaniga claims the ball just in time with Ba lurking behind him.
It's been quite a turnaround in the second period after Southampton had looked so assured and solid at the back.
Yet another break in play as Ramires needs treatment after a crunching tackle from Lovren.
Southampton force a corner which Davis takes but Wanyama and Fonte both have efforts blocked inside a packed 18-yard area.
Lampard sets Ba clear with a great long pass but the striker shakes off his marker but slips the ball wide of the far post.
Rodriguez is booked for dissent.
Gazzaniga does well to gather the ball with Torres and Ba waiting behind him.
Torres rises highest to flick on a long throw but it's that man Lovren who is once again on hand to clear.
The change is made with Schneiderlin replaced by Rickie Lambert.
A break in play with Schneiderlin needing treatment and it looks as though he will also have to come off.
Lampard picks out Cahill in the area with the free-kick and he heads down for Torres but he can't get it under control and Lovren stabs it away.
Morgan Schneiderlin is booked for a foul on Torres.
Southampton make another change with Steven Davis on for Ward-Prowse.
Mata's corner is headed out to Lampard on the edge of the box and he volleys a pass back outy to Mata whose cross is met by a glancing header from Terry which finds the top corner to mark his 400th Premier League appearance in style.
GOAL! Terry heads Chelsea into the lead.
Lovren then has to be alert to get the ball away from Hazard as he attempts to get on the end of a through ball from Torres.
Lovren uses his strength to ease Ba off the ball and quite rightly claims for a free kick are waved away.
Every incentive for Chelsea now - back on level terms and the chance to pressure a new keeper.
Boruc is unable to carry and is replaced by Paulo Gazzaniga who has not played a league game this season.
Boruc needs treatment after colliding with the post in his efforts to keep out the flick from Ramires.
Hazard's corner is met by Terry who heads goalwards and Boruc does well to keep out a touch from Ramiers but the ball breaks to Cahill who heads in his first goal of 2013 from close range.
GOAL! Cahill heads Chelsea level.
Wanyama brings down Torres and Lampard's free kick form 30 yards is tipped over by Boruc.
Ramieres brings down Shaw and it should be a booking, but it isn't and Ward-Prowse wastes the free kick.
Lallana is booked for dissent.
Lallana goes down 30 yards out after a challenge from Cahill but the referee waves play on.
Wanyama goes through the back of Torres but the offside flag is up and maybe that has spared him a booking.
Terry gets in an important header to deal with a cross from Lallana.
Torres earns his side a throw by closing down Clyne but again the visitors press to win it back.
Saints attack at the start of the half and they really do look confident in possession.
Chelsea make their second change with Demba Ba on for Essien.
"I would love to know what Jose Mourinho sees in Ivanovic as a right back as he is constantly caught out of position defensively, lacks the pace to keep up with good wingers and isn't able to put in a good delivery when he does get the ball in forward positions. Every game Chelsea play with people like Ramires, Lampard and Essien in holding roles makes Van Ginkel look even better. I cannot wait til the birthday boy gets back fit," says Karl Beake.
"Another substandard performance from Chelsea. The team has no fight, no drive, no leadership and no direction. Too many players of the same type, all wannabe number 10's and all too light weight. Chelsea have lost the air of invincibility at home and are always there for the taking," says Chelsea fan Peter from London.
Michael Essien's woeful back pass has gifted Southampton a half-time lead at Stamford Bridge. Jay Rodriguez was the grateful recipient as he stroked the ball home with just 12 seconds on the clock. Saints keeper Artur Boruc made a superb one-handed save to keep out a Fernando Torres header, but overall Chelsea have lacked a cutting edge in the final third and have consistently fallen into a well-organised offside trap.
Ramires is the latest to be caught in the Southampton offside trap.
We will have a minimum of four minutes added time.
How crucial could that save from Boruc be? It had goal written all over it until the Pole thrust out his hand to stop it.
Mata picks the ball up from the resulting corner but blazes over from 20 yards.
Hazard and Mata combine well to get in a cross which is met by a header from Torres that Boruc keeps out with a brilliant one-handed save going to his right before the ball is hacked clear.
Chelsea make a change with Lampard on for Oscar.
Torres does superbly to get in a cross when under pressure from two defenders and it is met by the head of Oscar but Boruc makes a fine save to his left.
Ward-Prowse cuts the ball back for Adam Lallana on the edge of the box but he scuffs a low shot well wide.
Indeed both do come back on, but seconds later Wanyama is down again after a foul by Ramires.
wanyama is first up and limps gingerly over the touchkline, followdd by Oscar so it looks as though both will continue.
A break in play with Wanyama and Oscar both down after seperate challenges and both seem to be in plenty of pain.
There is a very subdued atmosphere in the ground which is a sign of how well the visitors are playing.
Ward-Prowse delievers it to the far post and Lovren heads it back but the flag is up for offside.
The visitors have a free kick 35 yards out after a clumsy foul by Cahill on Rodriguez.
A bit of a lull in the game which will suit Saints who are knocking the ball around with confidence.
Essien's day gets worse as he is booked for simulation (diving!).
Essien gives Torres a ball to chase but Lovren is across and although the ball bounces up off him, Boruc gathers.
Boruc - not one the tallest keepers in the Premier League - does well to claim a dangerous Hazard free-kick in a crowded box.
You would think that in the course of 90 minutes Chelsea will spring this offside trap, but Saints are so well-drilled and organised so maybe they can just keep adding to Chelsea's growing frustration.
Essien gets in a header that loops just over - but it's offside again!
Ivanovic powers into the box but Shaw gets the ball off him with a well-timed tackle.
Good move by Chelsea ends with Ramires slipping the ball to Mata whose shot is parried by Boruc - but again the offside flag is up.
Job well done for Southampton so far with a quarter of the game gone.
Ivanovic concedes a free-kick 35 yards out on the angle and Ward-Prowse fires over.
Azpilicueta concedes a corner as he stops Clyne. Ward-Prowse takes it and again it is headed clear at the near post.
Torres turns well in the box and there are penalty appeals but it was another great tackle by Lovren.
Hazard's clever flick plays in the over-lapping Azpilicueta and his cross is met by Oscar but there is not enough power in the header to trouble Borus.
Chelsea are having a good spell here as they look to hit back from that shocking start.
Hazard takes a Chelsea corner that drops to Oscar 20 yards out and Boruc awkwardly parries his fierce shot but again the offside flag goes up.
Saints are using such a high line when they defend and Chelsea have not managed to counter it as yet.
Terry meets a cross from Mata but his volley goes way over - offside flag is up anyway.
Luke Shaw bombs forward down the Saints left but Branislav Ivanovic shrugs him off the ball and claims for a free-kick are turned down by referee Michael Oliver.
Saints keeper Artur Boruc is put under pressure by a strongly-hit backpass which he slices out for a throw but his side quickly win it back.
James Ward-Prowse's flag kick is low but disappointing as it is headed clear at the near post.
Great work by Osvaldo sees him shield the bal before winning a corner off Cahill.
Southampton have been comfortable so far and there is already some discontent among the home supporters.
A break in play as Daniel Osvaldo needs treatment, but walks off the field without too much trouble and will be able to carry on.
Vital tackle by the saints defender with Torres looking to get a shot away.
Torres runs at the heart of the Saints defence but is stopped by a fine tackle on the edge of the box by Dejan Lovren.
Essien has had a couple of decent touches since his early blooper and that will help his confidence.
Hazard is tripped in the centre circle and there are moans from the home fans as their side is denied taking the resulting free-kick quickly by the referee.
Chelsea have responded in positive fashion before Cesar Azpilicueta loses out to Nathniel Clyne and Saints have a throw.
The hosts force a corner taken by Mata and Cahill meets it but his looping header goes well wide.
What a start for the visitors! A reckless pass from Essien that was ounished heavily.
Southampton play the ball forward from the kick-off and Essien's attempted backpass is woefuul, straight to Rodriguez 16 yards out and he tucks the ball past Petr Cech.
GOAL! Jay Rodriguez gives Southampton the lead after just 12 seconds.
Saints get us under way with Chelsea kicking towards the old Shed End.
Chelsea fan Guy says: "It's a must-win for our boys today. There's plenty of flare in the midfield so let's do a job and show everyone we're still up for the title!"
"Would like to see Mourinho try his old formation - the diamond one - with Lampard In his best position playing behind the striker," says Phil from Hull.
"Great to see Mata in the lineup - I think he'll be the key to Chelsea's success this afternoon whilst trying to prove his worth. A little less support and more defence from further back without Lampard and Southampton to come in strong but I reckon another win on the record sheet for Mourinho," says Tim Coleman.
Our colleagues at Sky Bet have Chelsea very warm 4/7 favourites to win the game, with Saints 5/1 and the drawn on offer at 16/5. Juan Mata is 8/1 to get the first goal, with a Blues 3-1 success a 12/1 chance.
Will Masters say: "Should be an interesting game today, Southampton looking good and Chelsea need to bounce back from that midweek setback. I am predicting a 2-0 Chelsea win though as there seems to be too much quality in the squad to lose or draw at home."
"Southampton have taken me by surprise this season and it would be a magnificent achievement for them if they came here and stunned Chelsea, but I can't see them generating another shock this afternoon as the Blues never seem to perform poorly in front of their home crowd nowadays," says Chris Green from Huddersfield.
Juan Mata starts as one of four changes as Chelsea take on Southampton looking to cut the seven-point deficit to Barclays Premier League leaders Arsenal. Playmaker Mata, midfielder Michael Essien, striker Fernando Torres and forward Eden Hazard begin the first of nine December games for the Blues, who lost 1-0 to Basle on Tuesday night and were fortunate to scramble a draw from their most recent home match against West Brom. John Obi Mikel, Frank Lampard, Willian and the injured Samuel Eto'o are the players who make way against a Southampton side showing two changes from the side which began last weekend's loss at Arsenal, with Dejan Lovren and Dani Osvaldo replacing Jos Hooiveld and Rickie Lambert.
The teams have arrived nice and early and are as follows - Chelsea: Cech, Ivanovic, Cahill, Terry, Azpilicueta, Essien, Ramires, Hazard, Mata, Oscar, Torres. Subs: Cole, Lampard, Mikel, Schurrle, Ba, Willian, Schwarzer. Southampton: Boruc, Clyne, Fonte, Lovren, Shaw, Wanyama, Schneiderlin, Ward-Prowse, Lallana, Rodriguez, Osvaldo. Subs: Yoshida, Lambert, Steven Davis, Cork, Chambers, Gazzaniga, Hooiveld. Referee: Michael Oliver (Northumberland)
Good afternoon and welcome to our coverage of the Barclays Premier League clash between Chelsea and Southampton at Stamford Bridge. As always, we welcome your views so send them to firstname.lastname@example.org and I'll publish the best ones.