Steve Kerr’s simple game plan boils down to one point of faith.

“If it’s a halfcourt game, I really think our defense can get it done this series,” the Warriors coach said Sunday night.

The Warriors backed up Kerr’s well-earned confidence by holding the higher-seeded, homecourt Houston Rockets to their lowest scoring output of the season in a 95-85 win in Game 1 of what is shaping up to be a bruising first-round Western Conference playoff matchup.

The Rockets’ rebounding edge allowed them to take 11 more shots and they still couldn’t match the Warriors’ scoring output, thanks to a Golden State defense that held them to 39.1% shooting from the field and only six 3-pointers on 29 attempts (20.7%).

“I think, overall, we just flew around,” said Draymond Green, named one of three finalists for the NBA’s Defensive Player of the Year award earlier in the day. “We didn’t give up any easy looks. We followed our defensive gameplan. Just make them take tough shots.”

The Rockets’ aggressive, often literally hands-on approach to guarding Stephen Curry garnered attention after they held him to 3 points in their final regular season meeting, but it was the Warriors’ physicality that caught Houston coach Ime Udoka’s attention.

With it being the first postseason game for Alperen Sengun, Jalen Green, Amen Thompson and many others on the Rockets’ young roster, Udoka said he didn’t believe “the moment” got to them “but I would say (the Warriors’) physicality at times, just going after guys.”

Sengun was the only Rocket in double figures until midway through the fourth quarter and finished with 26 points — the only Houston player with more than 11 — but even he acknowledged afterward that, “I think we were ready ... I will say, I think we were nervous a little bit.”

Jalen Green, who averaged 21.0 points per game during the regular season, was held to 7 on 3-of-15 shooting, while playoff veteran Fred VanVleet went 4-of-19 from the field and 2-of-13 from distance. Jabari Smith Jr., who scored 11 points off the bench, said it wasn’t just a poor shooting night.

“Our spacing was a little thrown off tonight,” he said. “They were crowding the paint a lot on us. We’ve just got to figure out ways to counteract that. They were packing the paint, trapping Jalen (and) Fred, kind of funneling everything. They were trying to make us make the extra pass and we weren’t making it tonight.”

The Rockets ranked in the bottom third of the NBA in 3-point attempts in the regular season, and Kerr joked that it “felt like 1997 out there” with their physical, inside-the-arc style of play. They averaged 113.4 points per game, 13th-most in the NBA, but earned the No. 2 seed with their defense.

“They rough you up, they grab, they hold,” Green said. “They’re an extremely physical team and you have to give them credit.”

The Rockets’ defense ranked seventh in the NBA over 82 games. The Warriors’ has been the best since Jimmy Butler III arrived.

Green was asked if the win was any more satisfying given the circumstances.

“We just want to win the game,” he said. “We understand that in order to win, you have to defend at a high level. They’re the No. 2 seed because they defend at a very high level. ... But overall, Steph Curry usually finds a way.”

Curry finished with 31 points, Butler added 25 and the Warriors now hold homecourt advantage.

They knew the Rockets were going to get their offensive rebounds — and they did: 22 of them — but they could minimize their possession advantage by playing clean basketball. Houston outrebounded the Warriors by 16, took 11 more attempts from the field and six extra shots from the foul line but also turned the ball over 16 times to the Warriors’ 11.

“Our defense is big time, and we’re going to count on that,” Kerr said. “We need to recognize that we don’t need to take chances in this series. We need to be clean in our execution and transition. We don’t need to dribble through traffic. We don’t need to throw lob passes to try to get a dunk. We’ve got to be rock solid.”