Westbrook's performance against the Grizzlies followed double-doubles Tuesday night in a win over Atlanta (14 points, 11 assists) and Sunday in a victory over Indiana (26 points, 13 assists).
"I'm great, I feel good," said Westbrook, who was sidelined by a lateral meniscus tear to start the year. "I'm taking it one day at a time and I'm taking care of my body, which is most important. I'm trying to get us wins."
Kevin Durant, the NBA's leading scorer, added 18 points and six rebounds. Reserve guard Jeremy Lamb scored a career-high 18 points to help the Thunder to their fourth straight win and 12th in 13 games. Neither Westbrook nor Durant played in the fourth quarter, when the Thunder maintained a double-digit lead.
"Russell is calming down, relaxing and just playing his game," Durant said. "He is getting confidence. We tell him when he does no one can stop him."
Westbrook scored 12 points in the first seven minutes of the third quarter, including a three-point play after the Grizzlies had trimmed the Thunder lead to 13 points. The Grizzlies never got closer than 13 the rest of the way.
"Russell's a no-excuse player," Thunder coach Scott Brooks said. "We could play back-to-back, we could play four in five nights, we can play every night for a month and he's going to come in and play the game that he loves to play every night. He sets the tone for us and our guys do a great job following his lead."
Mike Conley had 20 points for the Grizzlies and Zach Randolph and reserve Jon Leuer scored 17 apiece.
Memphis ended a season-long six-game homestand with the loss.
A depleted Grizzlies' squad -- missing starters Marc Gasol and Tony Allen with injuries -- stayed close to the Thunder through most of the first half and trailed 40-37 after Conley's floater in the lane with 4:19 to go in the second quarter.
Then the Thunder put together a 17-5 run to end the half for a 57-42 advantage at the break. During the run, Durant had two driving dunks and Westbrook added a 3-pointer and four assists.
Oklahoma City opened the third quarter by extending its lead to 20 points as Westbrook scored nine points during a 13-8 start. The Thunder boosted their advantage to as many as 24 points in the second half on several occasions giving the Thunder the luxury of resting Durant and Westbrook.
"The first five minutes of the third quarter were probably the most important of the game," Westbrook said. "We wanted to come out and set the tone early defensively and we did a good job of that."
The Thunder were playing back-to-back games after defeating the Hawks Tuesday night in Atlanta.
The Thunder, who shot 61 percent in a win over Indiana on Sunday, shot 56 percent against the Grizzlies. Memphis shot 42 percent and was outrebounded, 42-33.
"The Thunder is a good team," Leuer said. "This is what they do. They go on runs. We tried to limit their easy stuff, but they got a few open looks and got into a rhythm after that."
NOTES: Thunder reserve center Steven Adams sprained his right ankle in the second half and didn't return. ... Grizzlies guard Tony Allen missed his fourth straight game with a right hip contusion and reserve forward Ed Davis missed his third straight with a left ankle sprain. ... The Thunder won for the first time this season on the second night of a back-to-back. They had been 0-2 in such games.