Match ends, Chelsea 2, Southampton 0.
Chelsea 2-0 Southampton
Olivier Giroud's brilliant semi-final goal helped Chelsea beat Southampton to reach the FA Cup final and set up a meeting with Manchester United.
Chelsea striker Giroud received the ball from Eden Hazard and jinked his way past two Southampton players in a crowded area before he stabbed the ball home.
Giroud was replaced by Alvaro Morata with 10 minutes to go and the substitute sealed safe passage with Chelsea's second when he headed in at the back post from Cesar Azpilicueta's cross.
Southampton went close with Nathan Redmond's low drive from distance while Charlie Austin hit the post.
It means Chelsea manager Antonio Conte will come up against managerial adversary Jose Mourinho at Wembley on 19 May.
There is no love lost between Conte and former Chelsea manager Mourinho, who have traded insults throughout the season.
The final is also repeat of 2007 when Mourinho guided Chelsea to a 1-0 victory over United in the first to be played at the rebuilt Wembley.
Victory over Mourinho could save Chelsea's season
Conte's Chelsea were beaten in last season's FA Cup final by Arsenal, albeit as a club which appeared much more harmonious.
They went into that final as Premier League champions and a domestic double would have put the gloss on a fine campaign.
This season has been a stark contrast with the London club struggling to finish in the top four to secure a Champions League place.
Rumours have also swirled over Conte's future at Stamford Bridge.
Victory in the FA Cup final will allow Conte to potentially provide a silver lining to what has been a difficult season.
To do so against Mourinho would also be particularly sweet for both Conte and Chelsea's fans, with the Portuguese's relationship with his former club having become strained since he took over at Old Trafford.
Encouragingly for Conte, there were flickers of the kind of form Chelsea showed at their best in that title-winning season in this game as they deservedly progressed.
Willian struck the crossbar after a rapid counter-attack, the impressive Hazard forced Alex McCarthy to tip the ball over the crossbar, while Morata twice went close at the end.
They will face much sterner opposition in United and Mourinho, though.
Giroud continues FA Cup love affair
Giroud won the FA Cup three times as an Arsenal player and his fondness for the competition continued against the Saints with the crucial first goal.
It ensured that the France striker has had a hand in 22 goals in 26 appearances in the competition since January 2012, with 15 goals and seven assists - more than any other player in the competition during that period.
Giroud had scored twice as Southampton squandered a two-goal lead against Chelsea to lose 3-2 in their Premier League fixture at St Mary's last weekend.
And after his strike at Wembley he has now scored eight goals at Southampton's expense. Against no other side has he scored more since he arrived in England.
It was a goal which provided the game's memorable moment. Giroud showed superb balance, poise and technique to finish as Southampton's players dropped like dominoes.
The 31-year-old was substituted by Conte with 10 minutes left and the hearty congratulations he received from the Italian provided the sign of a job well done.
His replacement Morata could have had a had a hat-trick as Southampton poured forward in attempting a dramatic comeback.
In the end, the Spain striker had to settled for one goal two minutes after he came on when he nodded in from close range.
Saints march back into survival battle
Mark Hughes was bidding to become the first Welsh manager to win the FA Cup, and take Southampton to their first final since 2003.
The Saints were organised and defensively disciplined in the first half as they restricted Chelsea to just two attempts on target before the break.
However, as soon as Chelsea took the lead a minute into the second half, it always looked an uphill struggle for Hughes' side.
As the game became more stretched, Chelsea always seemed the more likely to score - although Southampton did have their moments.
Hughes was frustrated after the Saints had a goal ruled out with the score at 1-0 when Chelsea goalkeeper Willy Caballero dropped the ball over his own line under pressure from Austin.
"The keeper Willy Caballero made a glaring mistake," Hughes said. "I don't know how they made that decision so quickly, Charlie Austin did nothing wrong..
"If ever there was a situation for VAR to step in and say we probably need to review that I would have thought that was the opportunity to do that."
Nevertheless there was an overriding feeling this match was of secondary importance to the issue of Premier League survival for Southampton, and Hughes can now give this his sole focus.
Southampton were a point above the drop zone when Hughes replaced Mauricio Pellegrino as manager.
They are now four points adrift of 17th-placed Swansea with four matches of the season remaining.
An FA Cup final would have been a bonus but results in forthcoming matches against Bournemouth, Everton, Swansea and Manchester City are what ultimately matter most for Hughes.
Man of the match - Eden Hazard (Chelsea)
'Need to put the this behind us' - reaction
Southampton manager Mark Hughes: "In the first half we didn't quite affect Chelsea as much as we talked about before the game so we were reasonably pleased to come in at half-time with it 0-0.
"Conceding first goal was always going to be detrimental. We took a centre-back off and they were able to capitalise with a second goal.
"We got a response but we didn't get any luck. We have a huge game next weekend and the focus now is putting this disappointment behind us very very quickly."
Chelsea boss Antonio Conte: "Now our target is to try and put a bit of pressure on the teams in front of us in the Premier League and get a place in the Champions League and finish as best as possible.
"It's important for us to reach a final in this competition especially because we are struggling a lot in the league.
"We are not in the position to prioritise (the FA Cup or fourth), if we want to continue to have hope of getting into the Champions League we have to take three points in these four games. Now we must be focused on the league."
Lucky 13 for Chelsea - the best stats
- Mark Hughes is just the second manager to be eliminated from the FA Cup as manager of two Premier League teams (Stoke and Southampton) in a single season, after Glenn Hoddle in 2000-01 with Southampton and Tottenham.
- Since they lost 3-1 to Southampton at home in October 2015, Chelsea have won each of six games against them in all competitions.
- Chelsea have reached the FA Cup final for the 13th time, and have got there in successive campaigns for the first time since 2009 and 2010.
- They have won seven of their eight FA Cup semi-finals at Wembley, with their only loss coming against Manchester City in 2013.
- Alvaro Morata has scored nine headed goals in all competitions this season; two more than any other Premier League player.
- All seven of Cesar Azpilicueta's assists this season have been for Morata.
Both clubs return to Premier League action next Saturday; Chelsea are at Swansea (17:30 BST), while Southampton host Bournemouth (15:00).
- 4FàbregasSubstituted forPedroat 76'minutes
- 22WillianSubstituted forBakayokoat 64'minutes
- 10E Hazard
- 18GiroudSubstituted forMorataat 80'minutes
- 37dos Reis Carvalho
- 35BednarekSubstituted forGabbiadiniat 78'minutes
- 3YoshidaBooked at 40mins
- 6HoedtBooked at 65mins
- 2Cédric Soares
- 18LeminaBooked at 55mins
- 14RomeuBooked at 50mins
- 23HøjbjergSubstituted forTadicat 63'minutes
- 7LongSubstituted forRedmondat 63'minutes
- Martin Atkinson
- Shots on Target
Second Half ends, Chelsea 2, Southampton 0.
Pedro (Chelsea) wins a free kick in the attacking half.
Foul by Oriol Romeu (Southampton).
Foul by Antonio Rüdiger (Chelsea).
Charlie Austin (Southampton) wins a free kick on the right wing.
Attempt missed. Pedro (Chelsea) with an attempt from the centre of the box misses to the left. Assisted by Eden Hazard.
Álvaro Morata (Chelsea) wins a free kick in the defensive half.
Foul by Maya Yoshida (Southampton).
Attempt missed. Charlie Austin (Southampton) right footed shot from the centre of the box is too high.
Attempt saved. Álvaro Morata (Chelsea) left footed shot from a difficult angle on the left is saved in the bottom right corner.
Eden Hazard (Chelsea) wins a free kick in the attacking half.
Foul by Cédric Soares (Southampton).
Attempt missed. Charlie Austin (Southampton) right footed shot from the right side of the box misses to the left. Assisted by Nathan Redmond with a through ball.
Attempt blocked. Álvaro Morata (Chelsea) left footed shot from the centre of the box is blocked. Assisted by Eden Hazard.
Charlie Austin (Southampton) hits the left post with a right footed shot from a difficult angle on the right. Assisted by Ryan Bertrand.
Foul by N'Golo Kanté (Chelsea).
Dusan Tadic (Southampton) wins a free kick in the defensive half.
Goal! Chelsea 2, Southampton 0. Álvaro Morata (Chelsea) header from the centre of the box to the top left corner. Assisted by César Azpilicueta with a cross.
Substitution, Chelsea. Álvaro Morata replaces Olivier Giroud.
Offside, Southampton. Dusan Tadic tries a through ball, but Charlie Austin is caught offside.
Substitution, Southampton. Manolo Gabbiadini replaces Jan Bednarek.
Attempt blocked. Emerson (Chelsea) left footed shot from outside the box is blocked.
Corner, Chelsea. Conceded by Maya Yoshida.
Substitution, Chelsea. Pedro replaces Cesc Fàbregas.
Foul by Olivier Giroud (Chelsea).
Wesley Hoedt (Southampton) wins a free kick in the defensive half.
Corner, Chelsea. Conceded by Alex McCarthy.
Attempt saved. Eden Hazard (Chelsea) left footed shot from outside the box is saved in the top centre of the goal. Assisted by Victor Moses.
Willy Caballero (Chelsea) wins a free kick in the defensive half.
Foul by Charlie Austin (Southampton).
Attempt saved. Oriol Romeu (Southampton) header from the centre of the box is saved in the centre of the goal. Assisted by Dusan Tadic with a cross.
Corner, Southampton. Conceded by Willy Caballero.
Attempt saved. Nathan Redmond (Southampton) right footed shot from outside the box is saved in the centre of the goal.
Corner, Chelsea. Conceded by Ryan Bertrand.
Olivier Giroud (Chelsea) wins a free kick in the defensive half.
Foul by Jan Bednarek (Southampton).
Corner, Southampton. Conceded by Antonio Rüdiger.
Corner, Southampton. Conceded by Olivier Giroud.
Attempt blocked. Charlie Austin (Southampton) header from the centre of the box is blocked. Assisted by Dusan Tadic with a cross.