OKLAHOMA CITY — Kevin Durant got back to playing like he's used to against a Memphis team that had to change things up at the worst possible time.

Durant scored 33 points, Russell Westbrook had a triple-double, and the Oklahoma City Thunder beat the Grizzlies 120-109 on Saturday night in Game 7 of their first-round Western Conference playoff series.

Durant looked like his usual self after struggling against Memphis' rugged defense for much of the series. The regular-season scoring champion made 12 of 18 field goals and all five of his 3-pointers after struggling from long range throughout the series.

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"I got out of my own way," he said. "I was thinking too much. I was worrying about what you guys (the media) were saying. I was worrying about what shots I was going to shoot throughout a game. I was thinking too much, and the game of basketball is played off of instincts.

"I just released everything and enjoyed myself. And I knew if I just put the work in for my team, the results would show."

With top scorer Zach Randolph suspended, the Grizzlies shook things up and traded their grind-it-out style for Oklahoma City's faster pace.

It worked for a while, but eventually, the explosive Thunder were just too much.

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Randolph was punished for punching Thunder center Steven Adams in the jaw late in Game 6, forcing Memphis coach Dave Joerger to make changes. Guards Tony Allen and Mike Miller started for the first time in the series in place of Randolph and Tayshaun Prince. The Grizzlies led by 11 points in the first half before the Thunder overwhelmed them and shot 66 percent after the break.

"We came out ready to play," Allen said. "We made a run, they made a run. Obviously, they capitalized in the second half. They kind of brought it to us in the second half and got the lead and we weren't able to recover after that."

Westbrook had 27 points, 16 assists and 10 rebounds. His assist total tied the franchise record for a playoff game set in 1987 by Nate McMillan when the team was still in Seattle. It was Westbrook's second triple-double in the past three games. He made 10 of 16 shots from the field, both of his 3-pointers and five of his six free throws.

"I think he chose his spots very well tonight, getting everybody involved, rebounding the basketball," Durant said. "But when we needed a basket, he was aggressive enough to get to the rim and make his pull-up jump shot. He just played a full game tonight."

Marc Gasol led Memphis with 24 points, and he made 10 of 11 free throws.

Point guard Mike Conley had 20 points and nine assists while playing with a strained right hamstring. He wasn't sure how much court time he would get, but he fought through the pain to play 36 minutes.

"Hats off to him," Memphis guard Courtney Lee said. "He has a pulled hamstring, and he's out there competing on both ends of the court. He took the challenge and said he wanted to guard Westbrook, and it just shows how much heart he has and his desire to win for this team."

It was a strange end to a series that mostly was played at Memphis' methodical pace and featured four overtime games. For a while, it looked like the Grizzlies' new approach would work. Memphis shot 60 percent in the opening period to take a 36-27 lead.

Oklahoma City chipped away in the second quarter, and the Thunder finally took a 51-50 lead on a 3-pointer by Durant. Durant hit another 3-pointer with 3.7 seconds left to give the Thunder a 61-58 lead at the break. He scored 21 points in the first half and Westbrook had 13 points and eight assists.

The Thunder opened the second half on a 10-2 run. Durant hit a 3-pointer to give Oklahoma City a 71-60 lead, and he hit another 3 that gave Oklahoma City a 78-63 advantage and led to a Memphis timeout.

The Thunder pushed the home crowd into a frenzy when Westbrook lobbed the ball to Jackson for a two-handed alley-oop dunk that pushed their advantage to 115-96.

It was a tough way for the season to end for the Grizzlies, who felt their season would have continued with Randolph available.

"What today showed was Z-Bo's worth," Allen said. "Showed how much he was missing today. I truly believe had he not gotten suspended, we probably would've advanced. But big hats off to all the guys who tried to fill in for his missing work."