It took until the 58th minute for former Newcastle midfielder Bruno Guimaraes to open the scoring at the Stadium of Light.
Arsenal then got their second goal from the penalty spot after Reinildo, who was shown a second yellow card, brought down Bukayo Saka.
Saka stepped up and Arsenal’s perfect start to the 2026-27 Premier League season continues.
Speaking to BBC Match of the day after the game, Le Bris was happy with his side’s performance despite the defeat.
"Frustrating result. Good game, especially in the second half. I think we went toe to toe with them and they are flying at the moment,” he said.
“We had the opportunity to score, I think it was deserved, (we) didn't score and thirty second after we conceded the goal. This is the level. I think they are relentless. When you don't seize your opportunities it's hard.
"The first half we were a bit reserved, respectful, knowing their threat and the way they play. The way they can damage your defence. So we were really well-organised, but we agreed at half-time it was important to show our quality with the ball.
“And that we did really well managing long balls at times and short balls when it was possible to play and we created chances.
"(David) Raya was one of the best players on the pitch today. It shows we are dangerous but not enough to score. We are really close. Winning is a process. They are at the top level right now.
“We were close this evening, it wasn't enough, but it was a good experience for us and our fans. We are getting better game after every game, it's hard to take but we need to go again.
"We have to believe and then it's a question of fine margins. Those fine margins are so hard to improve because it is the last percent and you need to work hard to get this one.
“We are in a good place. It's important to digest quickly because we have an impressive week ahead."