It's the Manchester Derby in FA Cup final

Man City's Erling Haaland (left) and Man United Marcus Rashford.[Twitter]

Victor Lindelof swept home the winning penalty kick against Brighton on Sunday to set up a first all-Manchester FA Cup final that could have so much more at stake than just the chance to win soccer's oldest competition.

For Manchester United and Erik ten Hag, it could cap a very encouraging first year under the Dutch manager with a second major trophy - after winning the League Cup - and a statement of intent for next season.

For Manchester City, it could be the second leg of a historic treble that would emulate United's feat in 1999 when it won the Premier League, Champions League and FA Cup all in the same season.

Given the fan rivalry and City's dominance over the past decade, the Wembley showdown is sure to be laced with tension.

"We will give everything and when I say everything, that is everything," Ten Hag said after United beat Brighton 7-6 on penalty kicks in their semifinal game at Wembley following a 0-0 draw through extra time. "But of course we want to give that against City. We want to give the fans that, for sure."

United's treble success was its crowning glory under former manager Alex Ferguson, with the Champions League secured in dramatic fashion when substitutes Teddy Sheringham and Ole Gunnar Solskjaer scored in second-half stoppage time to beat Bayern Munich 2-1.

While City has gone on to become the dominant force in English soccer since being taken over by Abu Dhabi's ruling family in 2008, the club has still never won the Champions League.

That could all change this season with Pep Guardiola's side advancing to the semifinals for the third year in a row and looking in ominous form on the back of a 16-game unbeaten run.

Man City's Erling Haaland celebrates after netting a hat trick against Man United.[Twitter]

City plays defending champions Real Madrid in the last four, so still has much to do to lift the one trophy it is yet to win.

A treble could be considered by some as final confirmation that the club has left United in its wake.

"I understand, of course, the feelings from the Man United fans about it," Ten Hag said. "We can do it, because we proved it. It's not an easy job though, it's a great team, but we also have a great team and great players and we can beat them."

Ten Hag has already led United to its first trophy in six years this season and is on course to secure Champions League qualification.

While there have also been lows, such as a 6-3 loss against City and the 7-0 rout by Liverpool, there is hope among fans that the club is on the way back up after 10 years since its last league title.

Victory against City in the FA Cup final on June 3 would be seen as further evidence that Ten Hag is ready to challenge Guardiola's supremacy.

City advanced to the final with a routine 3-0 win against second-division Sheffield United on Saturday, but United's route was much more difficult against a Brighton team that had the better chances through regulation time.

David de Gea had to make three saves to keep the game goalless after 90 minutes, pushing away an early free kick from Alexis Mac Allister and then pulling off another flying save to deny Julio Enciso in the second half.

Solly March's late effort was also stopped by De Gea.

Marcus Rashford was denied in extra time by Robert Sanchez.

March went on to miss the crucial penalty in the shootout, firing over the bar after both sides had scored their first six spot kicks.

United defender Lindelof struck the winner to spark celebrations from the red half of the stadium and ensure a potentially epic meeting with City.

"I think we deserved to win but (that's) my opinion," said Brighton manager Roberto De Zerbi. "We played better and we had more chances to score."

Man United's Wout Weghorst kisses the ball before passing it to Brighton's Solly March who missed the crucial penalty fr his team.[Twitter]

KISS OF DEATH?

Wout Weghorst scored United's sixth penalty in the shootout and then kissed the ball before handing it to March, who blasted his shot over the bar.

Whether or not that played any part in the Brighton player missing his spot kick, it might have been an act of gamesmanship from United's on-loan Dutch striker.

De Zerbi had supportive words for March afterward.

"In penalties anything can happen. You can make mistakes," he said. "March is one of the best players in our team and I'm proud of him and the rest of the players, especially today."

Rashford and Jadon Sancho both scored penalties after missing Wembley spot kicks in England's Euro 2020 shootout loss in the final against Italy.