Westbrook posted his ninth triple-double of the season on Friday to lead the Thunder to a 123-115 victory over the Eastern Conference-leading Atlanta Hawks.
The win came hours after the Thunder said that Durant would be sidelined indefinitely with nagging trouble in his surgically repaired right foot.
Durant has been out since February 22, and the news that he might not return for the last few weeks of the season seemed to dim the Thunder's playoff hopes.
Oklahoma City went into Friday's game with a one-game lead over the New Orleans Pelicans for the eighth and final playoff spot in the Western Conference.
Westbrook certainly isn't giving up. He notched his seventh triple-double in the past month with 36 points, 14 assists and 10 rebounds.
He had help, too, as the Thunder nabbed their fourth win in five games.
Dion Waiters contributed 26 points and Anthony Morrow scored 21, including 12 in the fourth quarter.
Seven Hawks players scored in double figures.
Pero Antic led the way, scoring a career-high 22 points off the bench. Dennis Schroder added 21 and Paul Millsap chipped in 19.
The Hawks led by as many as 12 late in the third quarter, but couldn't hang on and finished their six-game road trip at 3-3.