Manchester United manager Erik ten Hag said his players were "not ready" to start either half during their 2-2 draw with Leeds United.
Leeds scored 55 seconds after kick-off through teenage sensation Wilfried Gnonto and again three minutes after half-time to go 2-0 up at Old Trafford.
Ten Hag slams slow start
Second-half goals from Marcus Rashford and substitute Jadon Sancho earned United a point and while Ten Hag was pleased with the fight back, he admitted his team had paid the price for two slow starts.
"Definitely it was true that each half we are not ready," said Ten Hag.
"I start my talk at half-time with 'hey guys we are not ready, make sure you are ready' and then we go out [and concede again] and that is the point. I am disappointed we lost all the battles in the first minutes of each half.
"You can say we won a point because when you are in a derby and come back from 2-0 down it is good. But on the other hand when you start a derby like we did it's unacceptable. You have to be ready to fight and we weren't ready for the battle."
United headed into the game having won their last 13 games at Old Trafford but needed goals from Rashford and Sancho to come away with a draw against Leeds, who had not won a league game for more than three months and sacked manager Jesse Marsch on Monday.
Sancho came off the bench to score his first goal since September in just his second game back following a spell away from the club during the break for the World Cup.
Related content
07:57 - 09.02.2023
PREMIER LEAGUE Setback for Leeds in managerial search as Andoni Iraola turns down move
A delegation from Leeds has returned empty-handed from Madrid after failing to persuade the Rayo Vallecano head coach , Andoni Iraola, to take over from Jesse Marsch
17:39 - 08.02.2023
TRANSFERS Tottenham to rival Chelsea in pursuit of Diogo Costa
Tottenham are interested in signing Porto goalkeeper Diogo Costa as a long-term replacement for Hugo Lloris.
23:04 - 08.02.2023
PREMIER LEAGUE Sancho plays role of super-sub to rescue United against valiant Leeds
Manchester United’s 13-match winning run at Old Trafford came to an end after a pulsating 2-2 draw with Leeds United. The Red Devils fought back from two goals down to rescue a point.
14:32 - 08.02.2023
PREMIER LEAGUE Emir of Qatar ready to buy Manchester United for £4.5bn
The Emir of Qatar, Sheikh Tamim bin Hamad al-Thani, is interested in buying English side, Manchester United.