Martin Zubimendi and Viktor Gyokeres (2) struck the goals for Arsenal on Saturday.
Le Bris said: “The score is the score. Arsenal were relentless and showed their ability to seize the opportunities we gave them.
“Overall, we showed great personality and we were in the game until the third goal.
“We had opportunities to get back into the game, especially at the start of the second half.
“They are relentless, they are top of the league and top of the Champions League, so we know we played a very good team.
“We have to accept the score and take the lesson. Arsenal have built this team over many years, and we can feel that experience.
“They are really well-rounded in every part of their game.
“We are still a newly promoted side and we are doing well. We were competitive today, which shows we are growing through different experiences.
“The level is the level and you have to face it,” he continued. “When the opponent is stronger than you, it is difficult.
“We have to build on the strong sides of our game and analyse things to get better.
“We had three or four chances and you need to be clinical in those moments, but it wasn’t to be today.”