Match ends, Everton 1, Manchester United 2.
Everton 1-2 Manchester United
Anthony Martial's injury-time winner sent Manchester United into a record-equalling 19th FA Cup final with victory over Everton at Wembley.
Martial ensured Louis van Gaal's side will face either Crystal Palace or Watford with a composed finish in the dying seconds of an enthralling semi-final.
Marouane Fellaini gave United a deserved first-half lead from close range - but they were then indebted to goalkeeper David de Gea as he brilliantly saved Romelu Lukaku's 57th-minute penalty.
Everton rallied after a passive first 45 minutes that saw them jeered off at half-time and they drew level with 15 minutes left when Chris Smalling deflected Gerard Deulofeu's cross into his own net.
As the game looked destined for extra-time, Ander Herrera's poked pass sent Martial clear and the striker showed great composure to drill a low finish past Everton keeper Joel Robles.
Rooney excels in quarterback role
With England manager Roy Hodgson looking on, his international captain Wayne Rooney showed his class - and perhaps the future - in a deep-lying role behind United's attack.
In the opening half especially, afforded time and space by a timid Everton, Rooney not only showed his full range of passes to create chances and dictate the game, he even showed the energy to get back and clear Lukaku's early goalbound effort off the line.
Rooney's place in England's attack has come under increasing scrutiny with the emergence of Tottenham's Harry Kane and Leicester City striker Jamie Vardy as potential rivals, but this was the sort of performance that might just give Hodgson food for thought as he makes his plans for Euro 2016.
Lukaku's Wembley nightmare
Romelu Lukaku was responsible for bringing Everton to this semi-final with two goals and a powerhouse performance against Chelsea in the quarter-final - but he had a game to forget here.
He had two good chances in the first half but twice his touch was heavy and let him down, then when his big chance came from the penalty spot he was thwarted by an admittedly brilliant save from De Gea.
Lukaku simply could not find the magic touch and his face was a mask of bitter disappointment at the final whistle.
He has made regular noises about possibly leaving Everton in the summer - he will not do so with a trophy to his name after a performance that came up short.
Van Gaal trophy hopes live on
Manchester United manager Louis van Gaal has been surrounded by constant speculation about his Old Trafford future - but the dramatic conclusion here at Wembley means he still retains the hope of winning a trophy at every club he has coached or managed.
This was a two-faced United performance, excellent in the first half but ragged for much of the second and yet, as they have done through much of this FA Cup campaign, Van Gaal's team got the job done and are through to their first FA Cup Final since 2007.
Whether he survives as United manager or not, he has the chance to make sure United have silverware to remember him by. He will lead United out as favourites in the final.
What now for Martinez?
Martinez heard his players roundly jeered by thousands of Everton fans at they left the pitch after a dreadful first-half performance, but they were a team transformed after half-time and deserved to take this semi-final into extra time.
After the debacle of the 4-0 loss to Liverpool in the Merseyside derby, Everton at least regained some pride and credibility in a second half in which they turned the tide of this semi-final.
The bottom line, however, is that Everton once again conceded a last-minute goal - almost a trademark this season - and in a week that Martinez himself admitted was "defining", he has ended up a loser to both Liverpool and Manchester United.
With Everton's new major shareholder, Iranian billionaire Farhad Moshiri, watching from Wembley's directors' box, Martinez will at least have a hard-luck story to tell. Whether it saves his job is another matter altogether.
Man of the match - Wayne Rooney
The stats you need to know
- Marouane Fellaini has scored two goals in five FA Cup appearances this season - double his league tally (1 in 17 apps).
- Four of Anthony Martial's seven assists for Manchester United this season have come in the FA Cup.
- Romelu Lukaku has missed his last two penalties for Everton after scoring his previous five for the club (all competitions).
- Chris Smalling scored his first own-goal since April 2010 (all comps), when he did so against Everton while playing for Fulham.
- Martial scored and assisted in the same game for the third time this season.
- Martial has been involved in 21 goals for United this season, registering 14 goals and seven assists in all competitions.
- United have progressed to their first FA Cup Final since 2007.
- Everton have been eliminated in their last two FA Cup semi-final appearances, also losing in 2012 to Liverpool.
- This is the first time in three FA Cup semi-final meetings between the sides that United have been victorious, having been knocked out by the Toffees in 1966 and 2009.
- 4GibsonSubstituted forMirallasat 90+4'minutes
- 12LennonSubstituted forDeulofeuat 70'minutes
- 20BarkleyBooked at 89mins
- 1de Gea
- 51Fosu-MensahSubstituted forA Valenciaat 62'minutes
- 27FellainiSubstituted forHerreraat 87'minutesBooked at 89mins
- 10RooneyBooked at 58mins
- 9MartialBooked at 90mins
- 25A Valencia
- Anthony Taylor
- Shots on Target
Second Half ends, Everton 1, Manchester United 2.
Substitution, Everton. Kevin Mirallas replaces Darron Gibson.
Anthony Martial (Manchester United) is shown the yellow card for excessive celebration.
Goal! Everton 1, Manchester United 2. Anthony Martial (Manchester United) right footed shot from the centre of the box to the bottom right corner. Assisted by Ander Herrera.
Ander Herrera (Manchester United) wins a free kick on the left wing.
Foul by James McCarthy (Everton).
Corner, Manchester United. Conceded by Darron Gibson.
Ross Barkley (Everton) is shown the yellow card.
Ander Herrera (Manchester United) is shown the yellow card for a bad foul.
Foul by Ander Herrera (Manchester United).
Ross Barkley (Everton) wins a free kick in the attacking half.
Attempt blocked. Anthony Martial (Manchester United) right footed shot from the centre of the box is blocked. Assisted by Ander Herrera with a cross.
Substitution, Manchester United. Ander Herrera replaces Marouane Fellaini.
Attempt missed. Marcus Rashford (Manchester United) right footed shot from outside the box misses to the left.
Hand ball by Romelu Lukaku (Everton).
Attempt missed. Marouane Fellaini (Manchester United) header from the centre of the box misses to the right. Assisted by Antonio Valencia with a cross.
Attempt missed. Phil Jagielka (Everton) header from the centre of the box misses to the left. Assisted by Leighton Baines with a cross following a corner.
Corner, Everton. Conceded by Marouane Fellaini.
Attempt blocked. Romelu Lukaku (Everton) right footed shot from the centre of the box is blocked. Assisted by Gerard Deulofeu.
Attempt blocked. Marouane Fellaini (Manchester United) header from the centre of the box is blocked. Assisted by Daley Blind with a cross.
Corner, Manchester United. Conceded by Phil Jagielka.
Corner, Manchester United. Conceded by Leighton Baines.
Attempt blocked. Antonio Valencia (Manchester United) right footed shot from the right side of the box is blocked. Assisted by Marcos Rojo.
Attempt missed. Romelu Lukaku (Everton) header from the centre of the box misses to the right. Assisted by Leighton Baines with a cross.
Attempt saved. Gerard Deulofeu (Everton) right footed shot from the left side of the box is saved in the centre of the goal. Assisted by Ross Barkley.
Attempt saved. Anthony Martial (Manchester United) right footed shot from the left side of the six yard box is saved in the bottom left corner. Assisted by Michael Carrick.
Own Goal by Chris Smalling, Manchester United. Everton 1, Manchester United 1.
Foul by Jesse Lingard (Manchester United).
Ross Barkley (Everton) wins a free kick in the defensive half.
Attempt blocked. Wayne Rooney (Manchester United) right footed shot from outside the box is blocked. Assisted by Marouane Fellaini.
Foul by Marcus Rashford (Manchester United).
John Stones (Everton) wins a free kick in the defensive half.
Substitution, Everton. Gerard Deulofeu replaces Aaron Lennon.
Corner, Everton. Conceded by Antonio Valencia.
Foul by Marcus Rashford (Manchester United).
Phil Jagielka (Everton) wins a free kick on the left wing.
Attempt blocked. Romelu Lukaku (Everton) right footed shot from the right side of the box is blocked. Assisted by Muhamed Besic.
Attempt blocked. Marouane Fellaini (Manchester United) left footed shot from the left side of the six yard box is blocked. Assisted by Anthony Martial.
Attempt missed. Romelu Lukaku (Everton) header from the right side of the six yard box is just a bit too high. Assisted by Tom Cleverley with a cross.