Solly March, Brighton's seventh player to step up to the spot in the shootout, launched the ball over the bar, before Victor Lindelof found the net to secure a 7-6 shootout victory for United.
"It felt great," Lindelof told the BBC. "It was a great relief and we're glad to be in the final.
"I have confidence in myself and I knew which penalty I wanted to take and that's what I did."
The nail-biting finale was a fitting ending after 120 goalless minutes of wild swings in a game that careened from end to end all night.
The quality of the penalties in a torrential downpour was superb with United finding the net with all seven of their spotkicks.
Brighton's first six efforts were equally impressive until March fired wildly off target.
"They were great penalties," United keeper David De Gea said. "I was prepared as always. I tried to put pressure on the takers.
"There's still a long way to the final but it will be a big game against one of the best teams in Europe and the world."
Erik ten Hag's United, 12-times FA Cup winners, are chasing a cup double after winning the League Cup in February.
Treble-chasing Manchester City await in the final after they beat Sheffield United 3-0 in their semi on Saturday.
"We showed at home we can beat them (Manchester City) so let's hope," De Gea said. United beat City 2-1 in the Premier League at Old Trafford on Jan. 14.
"We are on the right track. One trophy, another final and fighting for the top four. It's not enough but it's a big step from last season."
Sunday's semi was a rematch of the 1983 final, when Brighton lost to United in the south coast side's only appearance in the showcase game.
It had fans on the edge of their seats at Wembley with numerous chances for both sides to break the deadlock, including several in extra time.
Marcus Rashford's deflected shot in the extra period was pushed wide by Brighton's diving keeper Robert Sanchez, and then he fired a long shot that sailed just wide.
Kaoru Mitoma nearly won it for Brighton late in extra time, but collided with De Gea in the box.
"It was a very tight game we played a very good team," De Gea said. "Brighton play really good football. We are now in the final but we have another big game on Thursday (against Tottenham in the Premier League) so we need to go home and recover."
The loss ended Brighton's superb run and ended The Seagulls' hopes of clinching a first-ever major trophy.
The FA Cup final is on June 3 at Wembley.
Ten Hag pleased with United response
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Manchester United manager Erik ten Hag reacts - FA Cup - Semi Final - Brighton & Hove Albion v Manchester United - Wembley Stadium, London, the UK - April 23, 2023. (Photo: Action Images via Reuters) |
Three days after a humiliating Europa League exit against Sevilla, United's victory at Wembley on penalties after a 0-0 stalemate was music to the ears of their Dutch manager.
"On Thursday I saw a team I didn't recognise but today we went back to usual," he said. "I could see determination and resilience. We fought for every yard and competed in every battle. We had good chances."
The normally measured Ten Hag was livid with his team's lack of effort on Thursday and admitted yelling at the players after their 3-0 rout for a 5-2 aggregate defeat in the quarter-finals.
"I can't accept that my team is not giving its best," said the Dutchman.
But there was nothing but positive words on Sunday after Victor Lindelof, United's seventh player to step up to the spot, slotted home the winning penalty after Brighton's Solly March missed by launching the ball over the bar.
It was the first-ever FA Cup semi-final shootout to go to sudden death.
"He is quite cool when it comes to penalties and he's quite cool in general," Ten Hag said of Lindelof.
United's manager was also pleased with his goalkeeper David de Gea, who was kept busy by several Brighton efforts.
"He made some brilliant saves. It hurt when he made mistakes on Thursday," Ten Hag said. "Often when you make mistakes as a keeper you get punished. We let him down, we didn't fight back for him. We bounced back today though."
Sunday's win set up the first all-Manchester FA Cup final, after City cruised past Sheffield United 3-0 on Saturday, and Ten Hag's second showpiece match in his first season at the helm after he guided United to a League Cup triumph in February.
"Whether Manchester United win the cup or not it's going to be a fantastic season for them. They've achieved all their goals this season. Erik Ten Hag deserves credit," said BBC pundit Alan Shearer.
Brighton had hoped to continue their dream run to what would have been their second FA Cup final before the wayward penalty from March, who hung his head crestfallen, hands on hips, after the miss while Brighton boss Roberto de Zerbi consoled him.
"In penalties anything can happen. You can make mistakes. March is one of the best players in our team and I'm proud of him and the rest of the players, especially today," De Zerbi said.
"(March) is sad but, I repeat, we have to close this day and tomorrow we have to think about another game. We need the possibility to forget. We want to achieve in Europe."
Brighton are eighth in the Premier League and battling to secure a European qualifying spot for next season.
