"Brighton is a team who normally wants to play from the back, they didn't today," Ten Hag said.
"They played long ball, so it's not about pressing, it's about winning the second ball, and then in such occasions, we did not always do what we laid out before the game and we definitely have to learn from those lessons.
"I didn't expect that this team would play long routines and I think it was a big difference. Our opponent have their routines, they are a long time together with a certain philosophy and a certain plan, cooperation between coach and team, you could see. And sometimes we are not.
"But still, it was unnecessary to lose this game."