Oklahoma City made eight of its first 10 3-point attempts in the second half and never trailed after scoring the final five points before halftime.
The Thunder had lost 110-93 to Brooklyn on Wednesday night, but were able to avoid posting back-to-back losses at home for the first time since dropping two of the first three games of the 2010-11 season.
"We've got to take advantage of our fans and take advantage of home court," Westbrook said.
Oklahoma City went 23 for 36 from the field, connecting at a sizzling 64 percent clip, while outscoring Philadelphia 63-43 in the second half.
"Our defense was really solid the whole night. The offense was a little slow, and coach told us going into the second half that we could score points so quickly, we just have to stick with our defense. That's what we did," Durant said.
Nick Young hit five 3-pointers and led Philadelphia with 21 points. He also attempted the Sixers' only eight free throws of the game, making six. Oklahoma City went 21 for 27.
"We've got to be stronger, take that ball to the basket and make them foul us," Philly coach Doug Collins said. "For one guy to shoot a free throw tonight, I'm not saying anything that that has anything to do with the whistle. So, I don't want that to be miscalculated at all."
Jrue Holiday had 15 points and nine assists, Dorell Wright contributed 11 points and Thaddeus Young scored 10 for Philadelphia. Spencer Hawes pulled down 13 rebounds. The Sixers fell to 2-5 on their eight-game road trip, which started before Christmas and concludes Saturday night at San Antonio.
The schedule soon flips for both teams. Philadelphia will play 13 of 15 games at home after facing the Spurs. Oklahoma City will try to maintain one of the league's best records while heading East, then on a pair of West Coast swings with brief stops at home in between.
"It's a good test for us to see where we're at. The road is always tough, no matter who you're playing," Durant said. "We've got to come out there and try to do a good job. We're looking forward to it."
The Thunder opened their first double-digit lead shortly after coach Scott Brooks came walking out on to the court to call timeout, screaming, "Let's Go!" at his players after Westbrook had turned the ball over by driving into the back of teammate Kendrick Perkins shortly after halftime.
Neither player made an attempt to run to the opposite end of the court, and Jason Richardson threw down a two-handed slam off Holiday's alley-oop.
Durant came out of the timeout and immediately drove into the lane, kicking the ball out to Thabo Sefolosha for a 3-pointer, and then drilled a 3 on the next trip down for a 56-46 advantage. Richardson answered with a 3-pointer, a layup and a runner for the Sixers before Westbrook scored six points during an 8-0 burst that pushed the lead to 69-57 for Oklahoma City with 3:50 left in the third quarter.
The Thunder salted it away with a 16-3 run late in the fourth quarter, as both teams started filtering reserves onto the court.
"They'll hit you with a surge, and that's what they did," Collins said.
After a tight first half that featured 14 lead changes, Oklahoma City scored the final five points of the first half to take a 46-42 lead and stayed in front the rest of the way.
"They kept making shots," Philadelphia's Evan Turner said. "They tried to counter off our turnovers and they got to running. The first half, we slowed the game down and didn't allow them to run."
Before the game, Collins offered his analysis of the Thunder's offseason deal that sent Sixth Man of the Year James Harden to Houston for Martin. "I think where you're going to see the value of James Harden is come playoff time. That's when," Collins said. "Because James Harden in so many instances, was their point guard and Westbrook scored and Durant. I think that's when you'll really see because in the playoffs, you need as many playmakers as possible. Kevin Martin can really score that ball but he plays off other guys. I think people don't realize James Harden also last year made more free throws in the fourth quarter than anybody in the NBA." ... Country star Vince Gill watched the game from a courtside seat along the baseline. ... Oklahoma City has played 20 of its first 32 games at home, going 17-3 at Chesapeake Energy Arena.