Westbrook was fined $25,000 on Sunday for directing inappropriate language at a fan in Dallas, after he was fouled by Salah Mejri on a drive to the basket during the Thunder's 119-108 victory Saturday.
Durant was penalized $15,000 for his flagrant foul 2 on Justin Anderson with 50 seconds left in the game. That led to his first career postseason ejection and second career ejection.
Durant said after the game that the refs' call was the right one, but he wasn't trying to hurt Anderson.
"It was just bad timing," Durant said.
Further discipline for Durant, including a suspension, is possible. The NBA office reviews all flagrant 2 fouls.
The Thunder lead the series 3-1.
Information from The Associated Press was used in this report.
KD gets ejected after flagrant foul
Kevin Durant gets a flagrant foul for smacking Mavs forward Justin Anderson in the face and gets ejected from the game.