Anthony Martial scored a dramatic 93rd winner as Manchester United stunned Everton to reach a record-equalling 19th FA Cup final following a thrilling semi-final at Wembley. Martial struck in the final minute of stoppage time to secure victory - a result which piles pressure on losing manager Roberto Martinez after a second damaging defeat in a row.
Marouane Fellaini's first half goal against his former club had looked like sending Louis van Gaal's side through to May's final after he converted from Martial's cross. David de Gea kept out Romelu Lukaku from the penalty spot with a stunning save but Chris Smalling's own goal drew the Toffees back into a contest which ebbed and flowed during an entertaining second half.
Both sides had chances to win it in normal time but with extra time looming, Martial exchanged passes with substitute Ander Herrera and finishing with aplomb past Joel Robles to breathe new life into Van Gaal's reign as United boss. Defeat meanwhile for an Everton side who improved dramatically after half time is the second damaging loss within a space of four days having been humbled by Liverpool in the Merseyside derby.
Each team arrived at the home of English football for their 12th meeting in the competition seeking much-needed respite following a season which had lurched from one disappointment to another. Martinez found himself under pressure after the sorry loss to Liverpool while United looked destined to miss out on next season's Champions League after a term during which they have plateaued under Van Gaal.
The disastrous loss at Anfield left Everton without the suspended Ramiro Funes Mori and injured duo Gareth Barry and Seamus Coleman but captain Phil Jagielka and John Stones passed late fitness tests. The Merseysiders could however cling to a decent recent cup record over United which saw them prevail on penalties in the 2009 semi-final and in the final in 1995 - scene of their last major trophy.
United, chasing a record-equalling 19th appearance in the final of the world's oldest cup competition, had belatedly rediscovered their scoring touch and that was reflected in an attack-minded line-up named by Van Gaal. Eighteen-year old Marcus Rashford partnered Martial and skipper Wayne Rooney - who joined Fellaini in starting against his former employers.
Despite coming off the back of a harrowing loss to their near-neighbours, it was Everton who scuppered a chance to take the lead inside five minutes. Lukaku shrugged off Chris Smalling and beat Timothy Fosu Mensah to the ball but having rounded De Gea a combination of a skewed shot and Rooney's headed clearance kept the score level.
Marcos Rojo flicked a Rooney free-kick wide but as Everton's early threat, which had revolved around Lukaku out-muscling Daley Blind and Smalling, waned United began to assert their authority. The 11-time winners should have hit the front themselves but Robles stood up to Jesse Lingard brilliantly after the 23-year-old had escaped the attention of Leighton Baines.
As the half reached the mid-way point, United's control began to grow with Rooney a central figure in an auxiliary midfield role. Martial smashed over and Rashford was denied by a low Robles save as Everton's back-four dropped worryingly deep. It was therefore little surprise that United took the lead before the break, when Martial, following a another driving run, crossed for Fellaini who stroked into the corner after evading the flat-footed Stones.
The half time whistle was met with a chorus of boos from the Everton support, but their team reacted in the second half with serious gusto. Referee Anthony Taylor rewarded a renewed performance by pointing to the spot after Fosu Mensah tackled Ross Barkley but Lukaku's run without a goal which had stretched to five games continued via a stunning one-handed stop from De Gea.
A frenetic start to the second half continued as Jagielka threw himself desperately in the path of Fellaini's close range effort which looked destined to beat Robles, until the England international's heroic goal-line intervention. Gerard Delofeu was introduced to maintain the Everton momentum, and with 15 minutes remaining a much-improved display led to a decisive equaliser.
Lukaku fed the Spaniard Delofeu whose cross bounced awkwardly in front of Smalling who could only turn the ball into his own net past the despairing De Gea. Everton sensed blood and only a full-length save from De Gea prevented Delofeu stroking home the winner as a now classic tie entered the final 10 minutes.
The chances continued to come for the five-time winners but Lukaku's minus touch continued to evade him, this time as Fellaini diverted his fellow-Belgian's effort behind. Martial's acrobatic strike hit Besic before De Gea's clearance ricocheted against Lukaku as each side searched for a late winner.
Extra time appeared to be looming until United popped up with a typically timely winner with just seconds left. Martial found Herrera, who threaded the ball back to the Frenchman, who duly tucked into the corner. While Everton are left to consider a season which has failed to match expectations, United's could end with silverware against either Crystal Palace or Watford next month in their first final for nine years.