Manchester United's problems continued to build after Brighton secured their place in the FA Cup fourth round with a 2-1 victory at Old Trafford.

Goals from Brajan Gruda (12) and Danny Welbeck (64) condemned United to defeat in what could well prove to be interim boss Darren Fletcher's final match before an appointment is made for the rest of the season, with Ole Gunnar Solskjaer and Michael Carrick the frontrunners for a post.

• FA Cup fixtures | Latest news
• Got Sky? Watch Premier League games LIVE on your phone📱
• Not got Sky? Get Sky Sports or stream with no contract on NOW 📺
• Download the Sky Sports app | Get Sky Sports on WhatsApp

Defeat to Brighton sees United, who were given a late lifeline by Benjamin Sesko (85) before Shea Lacey was shown a red card (89) for two quick-fire bookings, knocked out both the FA Cup and the Carabao Cup at the first hurdle of the competitions for the first time since the 1981/82 season, leaving them with just the Premier League to focus on as they look to qualify for Europe.

The full-time whistle was greeted with boos before near silence ensued with the Man Utd supporters and players left stunned by yet another lacklustre performance. The loss means United will play just 40 games this season - their lowest since the 2014/15 campaign when they played 44 games, and Fletcher said that the fans had every right to show their displeasure.

"Out of cups, only Premier League games to play for, the fans weren't happy at the end but they have got every right to air their grievances," the United interim boss told TNT Sports. "It wasn't toxic but they showed their disappointment. I'm sure if the payers show the right reaction, the fans will get behind them like they always do because there is still a lot to play for in the Premier League this season."

Whoever takes over will have to deal with mounting problems at Old Trafford, where there was a banner criticising the running of the club by Sir Jim Ratcliffe. There were also chants United fans are also chanting: 'We Want the Glazers Out.'

United, who sacked Ruben Amorim after 14 months in charge last Monday, are now without a win in four matches in all competitions and with games to come against Man City at the weekend and a trip to Arsenal, things don't get any easier.

Meanwhile, Brighton's fantastic recent record continues against United. Fabian Hurzeler's side beat United for the first time in the FA Cup. They now have seven wins in nine games against United and four victories in five visits to Old Trafford.

How Brighton secured a first FA Cup win over United...

Fletcher was given a warm welcome by Old Trafford as he emerged from the tunnel and his side started well, with a pair of early Jason Steele saves to deny Diogo Dalot and Bruno Fernandes keeping Brighton in the contest.

Brighton had been eliminated by United in the six previous FA Cup ties between them, but they were sent on their way to ending that hoodoo when Gruda reacted quickest to lash home the rebound after Georginio Rutter's header was cleared off the line.

Fletcher attempted to gee up the crowd when he returned, but there was little to cheer during a disappointingly slow start to the second period. Lacey and Joshua Zirkzee were introduced in a bid to change the dynamics, but just moments later Brighton extended their lead.

Welbeck received a pass from Gruda and was all too easily able to take a touch and slam a 65th-minute shot into the top left-hand corner.

"Attack, attack, attack," was the message from the United fans as they urged their side to get back into the game. Benjamin Sesko headed home Fernandes' corner to bring some hope, but United's day got worse with 18-year-old Lacey receiving two quick yellows in succession, the second for dissent, as a late equaliser evaded them.

Fletcher: The United players are fragile

Man Utd interim head coach Darren Fletcher to TNT Sports on the quad being devoid of any confidence:

"You can see that the players are fragile and they need to build themselves up. It's up to them now, they've got to respond.

"Confidence is one of the most powerful things in football and when you don't have it, you have to dig deep, you have to win, battle, fight, grind, work, win games and then the confidence comes back.

"They're experiened players, they're talented players and I challenge them to regroup. Someone is going to come in and lead them and they need to make sure they've got a lot to play for this season.

"This team is still good enough to have success this season, but they've got to dig deep and find a way within themselves."

Last game? "This is what I've been asked to do so I've not had any discussions beyond that. I did the job this week and we have to concentrate on the game. All the discussions around that will unfold in the next couple of days."

Dalot: Man Utd deserved to win

Manchester United defender Diogo Dalot to TNT Sports on his side's FA Cup defeat:

"We created enough to win the game to be honest.

"Then the red card gave us a disadvantage because we were on top of Brighton in the last moments.

"Overall, very disappointed because we wanted to go through. All the lads kept trying to find spaces, like I said really disappointed because I think we deserved to win.

On how it has been since the managerial change, he added: "Really difficult. It's always a period that you have to find ways to solve problems really quickly.

"We have to adapt and go again."

When is the FA Cup fourth-round draw?

Brighton will now have all eyes on the FA Cup fourth-round draw when it takes place on Monday.

The draw will be made at Anfield ahead of the last match in the third round between Liverpool and Barnsley.

It is due to start at around 6.30pm.

Play Super 6!

Super 6 have made a millionaire already this season, but could you be the next big winner? Enter the next round for free.