SAN FRANCISCO >> Steph Curry had never experienced a fire alarm during a game. Same with Warriors coach Steve Kerr.

Chase Center’s soldout crowd of 18,064 was ordered to evacuate Saturday night’s homestand-opening game after the first quarter, and roughly 20 percent of the fans headed for the nearest exit.

The all-clear signal was given a few minutes later on the false alarm, and what ensued was a 115-110 win over the physically formidable Detroit Pistons.

Along the way, Curry was honored for becoming the NBA’s 26th player to cross the 25,000-point threshold, and the crowd broke into an “MVP” chant as he sank four free throws in the final seconds to cap his 32-point homecoming after the Warriors’ impressive 4-1 East Coast trip.

Much of the postgame storylines centered on Draymond Green’s last-minute, go-ahead 3-pointer, Jimmy Butler’s winning touch, the Warriors’ ability to endure the Pistons’ bully-ball, and, of course, Curry’s legacy.

But there also was what Curry termed the “weird fire alarm.”

“They had the violinist out there and I thought it was part of her routine,” Curry said. “I thought it was a grand finale and thought, ‘That’s aggressive.’ Then you realize it’s real, and nobody knows what to do. There’s 19,000 people. Where do you go?

“Me and Draymond were laughing, because it took us a minute to get going physically after the long road trip and the quick turnaround,” Curry said. “None of us wanted to go back in the locker room, get stiff, then come back out and get re-warmed up. Thankfully everybody was safe.”

Added Warriors head coach Steve Kerr: “Somebody told us just to stay put. It’s the first time I’ve ever been a part of anything like that in my NBA career. It was a bizarre few minutes.”

Players on both teams remained on the court and loitered around their respective benches, with the Warriors ahead 22-20 after the first quarter. As the game resumed, Chase Center’s public-address system and music went silent for about 15 minutes, which Kerr said he was oblivious to while he was coaching one of the NBA’s hottest teams toward the playoffs.

Both teams entered with 35-28 records, so it shouldn’t have been too shocking that a tight, back-and-forth affair played out on this stage.

“It was physical. It was testy. A lot of pushing and shoving,” Kerr said. “To win a game like that, when clearly we were tired and trying to get our legs underneath us coming off that trip, it was a big-time win.”

It was their 11th win in 13 games since Butler’s Feb. 8 debut, via a trade that Kerr again commended general manager Mike Dunleavy Jr. for making.

“A month and a half ago, we would have lost that game,” Green said.

Only 35 seconds remained once Green gave the Warriors an insurmountable lead. Butler dished the ball to Green, who immediately launched a 3-pointer for a 110-108 lead. It was the third time in his career he hit a go-ahead 3-pointer in the final minute of a fourth quarter or overtime.

“Obviously we were trying to get the ball to Steph,” Green said. “… Jimmy threw me the ball and I knew I was shooting it when I caught it. I knew it was cash the second it left my hand.”

Butler made his own clutch bucket with 1:22 remaining, hitting a 12-foot, pull-up jumper to put the Warriors back in front. That gave him 26 points for his most yet in a Warriors’ uniform, surpassing the 25 he scored in his Chicago debut as well as Thursday’s win at Brooklyn.

“This is part of the Jimmy dynamic. He is built for these kinds of games,” Kerr said. “He’ll get us a shot, he’ll get to the line, and he’ll take big shots. Playoff Jimmy is a real thing, and in some ways that felt like a playoff game with the physicality.

“It was kind of a rock fight, frankly,” Kerr added. “Guys like Jimmy thrive in games like this.”

Added Curry: “It’s pretty clear as day the difference, not just the record but how we’re playing and how we’re winning and his impact.”

The Warriors opened the evening with a 9-0 lead, but they led just 22-20 after the first quarter, which is when the fire alarm went off and cast curious looks on everyone inside the 6-year-old bay-front home.

The Pistons and the Warriors then traded the lead throughout the second quarter (and the third and the fourth). Curry was scoreless for eight minutes after the false alarm; he had seven points in the first quarter to carry some momentum over from his sensational road show, which opened with a 56-point outburst in Orlando nine days earlier.

Curry was just 1-of-6 on 3-point attempts before halftime, and his teammates weren’t much better from there (4-of-20 overall). Curry finished 4-of-15 from 3-point range, 8-of-22 on all field-goal attempts, and 12-of-12 on free throws against the physically minded Pistons.

“Tonight was not a great shooting night for him, but I love how he played through fatigue and a physical night,” Kerr said. “That’s the mark of a great player.”

Curry crossed the 25,000-point mark during the third quarter and was honored with a photo montage on the video screens while he took a seat on the bench.

“(Radio announcer) Tim Roye told me after the game only 10 guys have done it with one franchise, so that’s pretty special,” Curry said. “The names are synonymous with basketball history, so that’s pretty cool.”

Butler opened the third-quarter scoring with a game-tying 3-pointer — his first of the night and only his fourth in 12 games with the Warriors. He hit another 3-pointer in the quarter’s closing minute.

The Warriors were outscored 32-12 in the paint in the first half, but that balanced out after halftime to the tune of 24-24.

“Very physical team. We knew they were going to come in and beat us up a little bit. That’s just how they play,” Green said. “They’ve kind of taken on that ‘Bad Boy’ moniker again, which I think is beautiful, especially because I’m from the state of Michigan.”