Erik ten Hag has admitted that he has a lot of work to do in order to get Manchester United back to where they want to be.
Ten Hag was appointed as United's new manager this summer after the club had endured their worst season in Premier League history.
One of the lowest points of United's miserable 2021/22 campaign had been a 4-0 thrashing at Brighton.
But United still started Sunday's season-opener against Brighton as strong favorites to get three points in Ten Hag's first EPL assignment.
Pascal Gross had other ideas though. The Brighton midfielder scored twice in the first half at Old Trafford.
United made a fist of it after half-time and got on the scoresheet with an Alexis Mac Allister own goal.
But despite the best efforts of Cristiano Ronaldo, Christian Eriksen and Marcus Rashford, United fell to a 2-1 defeat.
Speaking in his post-game press conference, Ten Hag noted that his team had improved in the second half but that much more is needed going forward.
He said, as quoted by the Daily Mail: "We made mistakes on the ball and organization mistakes in defending. We have to take the lessons and learn quickly from it.
"Brighton are a decent team, all the compliments, but I look to my team and we should not give two easy goals away."
Ten Hag added: "Definitely a setback and real disappointment. I knew from the start it would not be easy.
"It is clear to see the second half we were better in midfield with Eriksen down and Ronaldo up. We created and Rashford had two good chances, it is a shame we did not score.
"I am not satisfied, totally not. We lost and it was not necessary. We should do better."
Ten Hag was asked if he needed to sign more players in order for United to improve.
He replied: "We could do better with the players we had."
The Dutchman concluded: "It is a hell of a job. We have to work really hard, analyze, then move forward."