United won 2-0 via goals from Mason Mount and Benjamin Sesko.
Le Bris said: “We didn’t start well and got punished quickly. It is disappointing because we had good ambition coming here.
“We weren’t at the level expected in the first 30 minutes for the Premier League - not just about Manchester United but about us.
“They punished us, scored twice and after that it became another game. We changed our shape and it became a one vs one game. It was a bit chaotic but we tried until the end to score at least one goal."
Not at our best level
“The main takeaway from this game doesn’t define our start to the season,” he continued.
“When we are not at the level, I don’t think we can exist in this league. We are still a really young team with not much experience together.
“We need the ups and downs, but we don’t want ton be too negative when we lose.“It is a strong reminder and this is a good lesson for us today.”