United appeared to be in complete control after Shea Lacey and Mason Mount scored inside the opening 10 minutes. But Brighton turned the game around, with Charalampos Kostoulas, Pascal Gross and Maxim De Cuyper completing a dramatic fightback.

The defeat was United's third in six matches in all competitions this season and came just days after their controversial 1-0 Premier League loss to Manchester City.

It was also the first time in 50 years that United had lost a home match after leading 2-0.

Carrick refused to dwell on the growing criticism surrounding his team and instead challenged his players to respond.

"We all know it's there," Carrick said of the scrutiny. "How you deal with that is the important thing."

He added: "Being here toughens you up over a period of time, and it depends how you deal with it. You've got to deal with it in a way where you can cope with it and you can bring out the best in yourself."

United made a flying start when Lacey collected the ball inside the Brighton area after eight minutes and fired a clinical finish into the bottom corner for his first senior goal for the club.

Mount doubled the advantage only two minutes later, reacting quickest after Marcus Rashford's effort was saved by Jason Steele to smash the ball into the roof of the net.

But Brighton pulled one back in first-half stoppage time. United failed to deal with a defensive situation and Kostoulas took advantage, drilling the ball past Karl Darlow.

The visitors gained confidence from the goal and began to put United under sustained pressure after the break.

Gross levelled the match in the 65th minute, controlling Luka Vuskovic's header before finishing from close range.

United then fell apart again five minutes later.

Kostoulas found De Cuyper inside the area and the Brighton defender calmly swept the ball into the net from six yards to complete the comeback.

Carrick introduced Bruno Fernandes and Matheus Cunha as United searched for a response, but Brighton held on to secure their place in the fourth round.

The result was particularly painful for United because Brighton had already eliminated them from the FA Cup at Old Trafford in January.

Carrick, who guided United back into the Champions League last season during an impressive spell in charge, insisted he was not concerned about his own position.

"I don't feel under pressure," he said. "Either way, that doesn't bother me one bit."

The United head coach also backed his squad to recover quickly despite a difficult start.

"Of course we can turn it around," Carrick said. "We've got some really good players and it feels bad at the moment because we haven't had a great week, or two or three weeks.

"But it doesn't mean you can't win another game of football quickly."

United now have to respond when they travel to Fulham in the Premier League on Sunday, with the pressure increasing after another damaging night at Old Trafford.

Abraham leads Villa past Coventry

Tammy Abraham scored twice as Aston Villa beat Coventry City 3-1 at the CBS Arena to claim only their second win of the season.

Abraham put Villa ahead in the seventh minute before Victor Torp equalised with a superb free-kick.

Ross Barkley restored Villa's lead with a first-half header and Abraham struck again in the 59th minute to secure the victory.

Alcaraz sends Everton through

Charly Alcaraz came off the bench to settle Everton's tie against Wolves, curling home an 80th-minute winner as the Premier League side advanced with a 1-0 victory.

Fleetwood Town also reached the fourth round after becoming the lowest-ranked side remaining in the competition, beating Championship club Sheffield United 1-0.

Arsenal, Liverpool, Fulham and Brentford had already progressed on Tuesday, beating Ipswich, Tottenham, West Ham and Reading respectively.

Louis van Gaal set aside his principles to select 'extraordinary' Memphis Depay