Updated

HOUSTON (AP) -- Although James Harden is Houston's undisputed star, he can't top Russell Westbrook entirely on his own.

As is so often the case, Patrick Beverley was there for support Sunday night.

Harden scored 37 points to outshine Westbrook, and the Rockets pulled away in the third quarter and coasted to a 118-87 victory over the Oklahoma City Thunder in Game 1 of their first-round playoff series.

Harden had nine assists and seven rebounds, and Beverley, who had the unenviable task of guarding Westbrook, had a playoff career-best 21 points along with 10 rebounds.

Beverley's performance was nothing new to Harden, who has had a front row seat to his work for years.

"That's the reason we're in the position we're in," Harden said. "He brings it every game. Whether his shot is falling or not, he brings that intensity, that resolve. He was just Pat tonight."

The best-of-seven Western Conference series continues Wednesday night in Houston.

The third-seeded Rockets were up by 20 when Harden came off the bench with about seven minutes remaining. He went right to work -- making two 3-pointers to power a 10-0 run and push the lead to 110-80 with 4 1/2 minutes left. Harden, who along with Westbrook is a front-runner for MVP, went to the bench, and both teams cleared their benches soon after that.

Westbrook had 22 points, 11 rebounds and seven assists, but made just 6 of 23 shots and had nine turnovers for the sixth-seeded Thunder.

"We've got to do a better job starting with myself -- got to do a better job of taking care of the basketball and making some shots," Westbrook said.

Beverley refused to take credit for slowing Westbrook down.

"It was a team effort in just trying to show him a lot of bodies," he said. "He's one of the most explosive guards in this league, so we were just trying to make it tough on him."

The Thunder trailed by 15 entering the fourth quarter, and six straight points by the Rockets extended the lead to 100-78 with about 7 1/2 minutes remaining. Lou Williams scored the first four points in that span, and Beverley found Clint Capela on an alley-oop dunk.

The Rockets scored the first five points of the second half to push their lead to 10 early in the third quarter. After a timeout, Oklahoma City scored the next eight points with 3s from Westbrook and Andre Roberson to cut it to 64-62 with about 8 1/2 minutes left in the quarter.

Houston scored the next nine points, capped by consecutive 3-pointers by Beverley to make it 73-64 midway through the period.

Beverley went to the bench soon after that to a huge ovation and a high five from Houston Texans star J.J. Watt, who watched the game from a courtside seat.

Thunder coach Billy Donovan raved about Beverley.

"He played a very, very good game," Donavan said. "I thought he impacted the game way, way more with his energy, his effort, his hustle, his loose balls, his offensive rebounding, keeping balls alive. That's where he really did a great job."

Westbrook ended a scoring drought of almost 3 1/2 minutes for the Thunder with a layup, but Houston used an 8-2 spurt -- highlighted by a 3 from Eric Gordon -- to push the lead to 81-68 with just more than three minutes remaining in the third.

Harden made a pair of free throws to cap the third quarter and leave Houston up 89-74 entering the fourth.

For Houston coach Mike D'Antoni, it's the first postseason win since April 27, 2008, with Phoenix. D'Antoni's teams were swept in the first round in his last two trips to the playoffs in 2011 with the Knicks and 2013 with the Lakers.

Houston's victory comes after the team went 3-1 in the regular season against the Thunder.

The Rockets led 59-54 at halftime.

TIP-INS

Thunder: Roberson added 18 points with seven rebounds. … Oklahoma City, which led the NBA in rebounding in the regular season, was outrebounded 56-41. … Jerami Grant had 10 points.

Rockets: Capela missed a few minutes in the second quarter to receive three stitches in his lip. He had 14 points and seven rebounds. … Nene had 15 points. … Houston had 31 second-chance points to just four by the Thunder.

THEY SAID IT

Thunder center Steven Adams on Oklahoma City's performance: "We were just trash on the reads, on the pick-and-rolls. We were just absolutely garbage. We just have to go back to the drawing board and figure it out before Game 2."

PUTTING THE WIN IN PERSPECTIVE

D'Antoni wants to make sure that his team realizes it still has a lot of work to do despite its big win.

"All we did is defend our home court, and that's what we're supposed to do," he said. "It's nice to play well and get the win because you have to, but this is just one little step … in the big scheme of things. I'm sure they'll bounce back, and we've got to be ready to go."

UP NEXT

Oklahoma City will remain in Houston for two days of practice before Game 2 on Wednesday night at the Toyota Center.