United were architects of their own downfall at the Amex Stadium, making mistakes in the build up to the two opening goals scored by Glenn Murray and Shane Duffy.
Romelu Lukaku briefly halved the deficit but a clumsy challenge from Eric Bailly allowed Pascal Gross to restore Albion’s two-goal lead with a penalty, before Paul Pogba converted an inconsequential stoppage-time spot-kick.
United manager Mourinho blamed individual errors for the surprise defeat and feels it could be damaging for morale.
“The confidence of the players, I think you are right,” replied Mourinho, when asked if it would be difficult to raise the spirits of his team.
“It’s not just the players, I think every person in every job makes a mistake, he’s not happy, self esteem goes down a little bit more, confidence levels, that’s human nature.
“If you ask me if my players are, in this moment, happy, I don’t think they are.”
Brighton, who beat United 1-0 in May to make sure of their top-flight status, repeated the trick by blowing away their opponents in the opening 45 minutes.
Striker Murray took advantage of shoddy defending to superbly flick home the 25th-minute opener, and centre-back Duffy converted two minutes later after the visitors failed to clear a corner.
Lukaku’s close-range header looked like it could inspire a fightback, but Gross’ spot-kick, after he was felled by a clumsy challenge from Bailly, secured the three points just before the break.
Pogba, captaining United, made the scoreline more respectable with almost the final kick of the game following Duffy’s foul on substitute Marouane Fellaini.
Mourinho refused to openly criticise his players, saying he had been too honest in the past and suggesting the defeat was sufficient ammunition for journalists.
“I think this game today, if I was in your position, would give me (enough) material to speak about it or to write about it,” added Mourinho, addressing the media.
“Don’t expect me to speak with you about it because you and your colleagues they were really critical with me in previous seasons (when) I was probably too honest, too open in my analysing.
“Expect from me to be really happy to say after Leicester (a 2-1 win), A, B, C, D, amazing performances, this and that; don’t expect me to go in the other direction.”
Brighton boss Chris Hughton was pleased to record another memorable victory over United and bounce back from last weekend’s disappointing defeat at Watford.
“Very proud of the performance, particularly the reaction from last week,” said Hughton.
“The tempo of the game was very good and I must admit, even if we hadn’t got the result, I would have been really delighted with the way our team played the game and the levels that we got to, to try and get a result.
“And I would like to think that most people watching the game would look at it – I know once it’s a big-six team that others will look at it a little bit different – that we were good, as opposed to United being poor.”
First-half goals from Albion trio Glenn Murray, Shane Duffy and Pascal Gross inflicted defeat on United, with Romelu Lukaku pulling one back before Pogba scored a late consolation with a penalty.
Here, Press Association Sport analyses Pogba’s performance at the Amex Stadium.
Pogba lined up on the left side of a three-man central midfield, with Andreas Pereira as the anchor man and summer signing Fred further right. The 25-year-old was often the most advanced of the trio, looking to assist central striker Lukaku and wingers Juan Mata and Anthony Martial. His defensive responsibility appeared limited. In the second half, he was deployed in a deeper position after Pereira and Mata were replaced by attacking England duo Jesse Lingard and Marcus Rashford.
Pogba slipped through Lukaku in the opening 10 minutes but the Belgium international squandered the opportunity. He was guilty of a risky pass to Pereira in the build up to Brighton’s opening goal, while a sloppy ball across goal to Eric Bailly just after the restart almost let in Solly March. He conceded possession on a number of occasions with poor distribution, including a pass which went straight out of play for a Brighton throw-in.
The World Cup winner’s languid style can make it tough to accurately assess his demeanour but he certainly looked frustrated as his team once again struggled on the ground which was the scene of a 1-0 defeat in United’s penultimate away trip of last season. He was repeatedly seen expressing his displeasure by waving his arms about, particularly in a second period in which United showed little sign of fighting back.
Pogba was on target from the penalty spot in United’s opening win against Leicester and he again converted from 12 yards here, although it was too late to make a difference. His first-half cross-shot sailed harmlessly over, and he was unable to break into the box after being dropped into a more defensive role by manager Jose Mourinho at the break. A shot from range with 15 minutes remaining was tipped wide by Albion goalkeeper Mat Ryan.
Pogba is reportedly unhappy at Old Trafford and he did little to quash those rumours with his display on the south coast. He had little impact on the game and his attempts to galvanise his team-mates during a torrid first half in which they conceded three times appeared half-hearted. United were desperate for a leader to help inspire a second-half response but Pogba seemed more intent on bemoaning the situation before converting an inconsequential spot-kick deep into stoppage time.
“This is real,” said the 31-year-old amidst frenzied scenes as he touched down in Sydney on Sunday.
“I’ve said it since my last season of track and field that I wanted to play football and I knew what I’m capable of. I know what I can do.”
Bolt’s foray into football, including previous sojourns with Borussia Dortmund and Stromsgodset in Norway, have been seen by some as nothing more than a gimmick, but the man himself insists it’s no joke.
“They (the Mariners) gave me a great opportunity and I’m really happy about it,” he continued.
“I’m just going to come here and do my best as always. I always put my best foot forward and I’m just going to show the world I’m here.”
The Mariners home ground, the Central Coast Stadium, has a capacity of just 20,059 and is a long way from the great stadiums of the world which Bolt is used to filling, but he says he feels at home in Woy Woy as much as London or Rio.
“As you all know I love Australia, so I’m happy to call Australia home for now,” Bolt told a delighted crowd.
“I’m more excited than anything else.”
The Mariners will certainly welcome the presence of the triple world record holder with attendance and interest down as the club has finished in the bottom three in the last four seasons and last in 2017/18 and 2015/16.
A far cry from their titles of 2007/08 and 2011/12, the second under now national coach Graham Arnold.
And certainly Gosford and Wyong, the central hubs of the Central Coast and just a short hour long drive north of Sydney, will welcome the exposure to promote themselves more as a tourist destination.
Bolt does not see this as a short term adventure.
Asked how long he plans to stay in the region, Bolt replied: “Forever hopefully.”
“I’m here for a trial period, but I’m going to push, work hard and show what I’m capable of. I’m sure my best foot forward will make it.”
Bolt has a little under two months to prove his worth as the Mariners’ season kicks off on Sunday October 21 when they face the Roar in Brisbane.
The Jamaican once dreamed of Olympic glory – that dream came true.
This second dream may be a little harder to achieve, especially with the whole world watching.