Manchester United hit a new low under Michael Carrick as they threw away a two-goal lead to lose 3-2 to Brighton - and exit the Carabao Cup at the first hurdle for a second straight year.

It is the first time in 50 years that United have held a 2-0 lead at Old Trafford and lost the game. They had won 143 out of the 145 previous times they had raced into such an advantage.

Yet it was all going to plan for Carrick's side as they looked to respond to the Manchester derby defeat, as talented teen Shea Lacey and Mason Mount put them in control after 10 minutes.

But United began sleepwalking towards defeat - failing to register another shot on target until the 76th minute - and Brighton, who made six changes for this cup tie, took advantage.

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After Charalampos Kostoulas pulled one back on the stroke of half-time after questionable goalkeeping from Karl Darlow, the Seagulls struck twice in four second-half minutes through Pascal Gross and substitute Maxim De Cuyper to stun Old Trafford into silence.

Bruno Fernandes was then brought on as an emergency substitute, before Marcus Rashford missed a one-on-one chance to level the cup tie.

Boos rang out at Old Trafford at full-time, with United fans singing: "What the f****** hell was that?" to their team.

This was not quite the second-round embarrassment at Grimsby that Ruben Amorim suffered last season, but Carrick now has a lot of questions coming his way as one of United's realistic trophy hopes disappears for another year.

WATCH: How Brighton fought back!

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The key moments from Old Trafford

8: GOAL! Lacey initially makes it a dream full United debut by skipping past two Brighton defenders before finding the near post

9: GOAL! Forty-three seconds after the restart, Mount makes it 2-0 after Jason Steele saved from Marcus Rashford.

36: BIG CHANCE! Brighton respond well after the early double deficit but Malick Yalcouye curls a one-on-one chance wide.

45+1: GOAL! Kostoulas beats Darlow to a long ball into the box and slots in a leveller, despite United complaints Benjamin Sesko had been fouled in the build-up.

65: GOAL! Gross converts from close range after Sesko headed the ball back to him after losing 50:50.

69: GOAL! Old Trafford is stunned as substitute Diego Gomez goes on lengthy run and crosses for De Cuyper, who finishes from close range.

76: HUGE CHANCE! Rashford is played through on goal but his near-post finish is kept out by Steele.

84: TWO CHANCES! Brighton miss a double chance to seal the game as Kostoulas' effort is cleared off the line by Leny Yoro, before Gomez's shot is saved by Darlow.

Carrick: We can't accept that

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Man Utd head coach Michael Carrick to Sky Sports:

"We can't accept that as a group. I take responsibility for it. The performance towards the end of the second half, that's on me.

"We'll all be better. We have to be better. We have a big game on Sunday that we have to prepare for. We're out of this competition and we have to go back to winning football matches."

What do you need to do to get better? "We'll get better on a number of things."

Is he feeling the boos from the fans? "Yeah of course, that's pretty obvious! I totally understand the feelings of the supporters.

"We have to accept it. I totally accept it. It's on me ultimately: as a team what we look like, how we play and what results you get. I take that. I'll take the praise, I'll take the criticism and the upset.

"I totally understand it for the way the game went. We have got to win games."

Analysis: When will it end at Man Utd?

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Sky Sports' Sam Blitz:

Manchester United just haven't changed have they? Year after year of failure.

Go back to August 7 2022; it was a similar picture to now at Old Trafford. That was the day Brighton won 2-1 at Old Trafford with Pascal Gross scoring twice and pulling the strings.

Four years later, at the age of 35, Gross is still pulling those same strings - a sign of the German's great longevity, but also a sign of United's failure to progress anywhere.

That match was 1,502 days ago and saw Erik ten Hag's tenure get off to a horrendous start. United have gone through four other managers in those four years since then. When will it end?

Hurzeler: I didn't think we started that bad!

Brighton head coach Fabian Hurzeler to Sky Sports:

"We started the game really well. We conceded two easy goals and we stuck to the plan. That was the positive thing.

"When you're 2-0 goal you can go in one direction and say the game is done and don't stick to the plan anymore. Or you have to believe in yourself and the match plan and finish doing it. The longer the game went, the better we were. And we won a deserved win.

"I didn't think we started that bad. We conceded goals and goals change momentum but we had the right structure and good patterns. We weren't clean. The bad thing is we were quite nervous, making technical mistakes and then the players grew into the game.

"In the end, we completely controlled the game. We had plenty of chances to score another goal. But I had a feeling in the beginning that some players were nervous."

Your views: Fans debate if Carrick is the issue - or it is something bigger?

Ian B: How much time does Carrick have? I don't think it's fair to judge after just 5 games but how long would they wait? When is 'not good enough' too deep of a hole? Must be pre-Christmas surely?

Elb12: Carrick sacked during international break. Thrown under the bus. I can't remember the last time United won a game in which there was a win and good performance. I had no confidence we'd win that game even at 2-0. United are finished no way back until the owners sell.

Gmw1966: We are never safe in a game. Our defence is poor. Our full backs are barely average. This isn't a surprise. We got lucky in a lot of games last season. Carrick brought stability, but he's limited tactically. Fulham becomes a huge game now.

Johhny_Land: Carrick has been massively let down by the board and it's so clear to see. Can't even blame him when his defenders don't even seem to be able to kick a ball. Absolutely woeful.

Sol: There are no tactics, we had a new manager bounce with a sprinkle of luck. There are no tactics and there isn't a plan. There needs to be a manager, Carrick is a positive figure for the club but not the manager.

Caseymufc1983: Poor again from the team. But we cannot continue to sack managers. Its becoming embarrassing. Historically, clubs that retain the boss year after year, tend to have more successes as opposed to a new manager after a run of poor game's. Back to the drawing board.

Dom: How much longer do we keep blaming the manager? This is the same group of players who got the same amount of points and dominated a City team at Old Trafford last season. Players are doing to Carrick what they did to Solksjaer.

Ossy: Fitness/intensity and Carrick's inability to read game state and react accordingly, is going to be Man Utd's undoing this season. The club needs to act fast before it spirals out of control. If the losing continues, it becomes more difficult to snap out of it.

Richards: Same issues as United have had for 13 years. People will blame the players or the manager but these are different players, a different manager, to 10 years ago but identical performances. No intensity, no control, can't press, can't play through teams the list goes on and on.

Mike S: Tactically all wrong. No control in the midfield, no no one with the creativity to break down Brighton. Defensively awful in transitions. Carrick has got some work to do to earn the trust of the fans again and find a way to stop us conceding so many goals!