A late penalty converted by Habib Diarra earned the points for Sunderland after Ethan Ampadu was judged by VAR to have handled the ball.
Speaking post-match, Le Bris said: “Football is unpredictable but I am really proud of the players tonight.
“We are proud because we were really well-connected and showed great character. It was a tough game and intense - it was a question of key moments.
“We were well aligned to seize our opportunities and it was an important win. Leeds played with an unusual set-up so we had to adapt our structure to press them.
“The Lads did really well and I am impressed because we didn’t work on this.
“We explained the ideas but then you have to execute.
“We struggled in the first 10 minutes but after that we were brilliant.
“I am proud of the flexibility of the squad and the way they worked together to manage this problem.”