Brighton coach Graham Potter, formerly of Östersund, on the other hand, had a tasty start to the season as his team took all three points from Old Trafford.
The visitors' midfielder Pascal Gross scored twice in the space of nine minutes and the United players got to hear what the home crowd thought of their performance at half-time.
They were booed.
In United, Victor Nilsson Lindelöf was not even on the bench due to a thigh strain according to information.
On the bench, however, was Cristiano Ronaldo.
The Portuguese has been the subject of rumors recently and has been reported to want to leave Manchester United.
He played one half of the training match against Spanish team Rayo Vallecano on Sunday and then left the arena.
Something for which he was criticized by new coach Erik ten Hag.
Eight minutes into the second half, ten Hag chose to replace Ronaldo - and a quarter of an hour later it was reduced at Old Trafford.
After a semi-messy situation in the penalty area, Alexis Mac Allister finally kicked the ball into his own goal.
1-2 so far.
United were chasing an equalizer and in the 90th minute Anthony Elanga was substituted to try and contribute to a 2–2 result.
But it was not to be, Brighton held on and won the premiership with 2–1.
In the other 15.00 game in the Premier League, it ended 2-2 between Leicester and Brentford.
Pontus Jansson played the entire match for Brentford.
In the next round, Manchester United face Brentford away.