DALLAS — The American Airlines Center was quiet, resembling a 20,000-seat library. You could have heard a pin drop on the hardwood.

And then Cooper Flagg got going.

The Newport native started attacking the basket, blocking shots and throwing down dunks. Suddenly, the Dallas Mavericks were closing in, and the crowd was alive. What felt like a Friday night snoozer had transformed into a playoff feel, and by night’s end, thunderous cheers were punctuating what became a 118-115 Mavericks win over New Orleans.

Just Cooper being Cooper, Dallas coach Jason Kidd said.

“We’ve seen this before, right?” he said. “He’s done that before in this building, especially when he goes coast to coast, being able to come up with a steal or a 50/50 ball, going behind his back, and then being able to finish with a layup or a dunk. I think the crowd is always waiting for that moment, and I think he’s delivered.”

Here’s a few observations from a Maine reporter at a pair of Mavericks games in Dallas last weekend.

How it looks

There’s no outward sign at the American Airlines Center that Flagg is the face of the franchise. While there is a banner with his image by one of the doors, it’s veteran stars Anthony Davis and Kyrie Irving who are on the big display by the south entrance, which leads out to the PNC Plaza and the major gathering area for fans.

The arena itself is massive, with fans walking through giant brick facades and arches into a building with high ceilings. By the entrances, the arena looks almost like a hotel, with balconies and suite doors visible a floor above the concession stands. The corners, however, are rotundas, and make you feel as if you’re in a state capitol building.

Signs and advertisements with Flagg’s likeness don’t bombard you upon entry. It’s not like when LeBron James was drafted by Cleveland and his “Witness” Nike ads popped up everywhere.

Where you see Flagg’s impact is in the thousands of jerseys on people in the concourse and the stands, his No. 32 seeming to overtake Kyrie Irving’s No. 11 as the biggest seller among fans.

“That’s Flagg,” one father walking behind one of those jerseys said to his young son. As if sensing his son needed clarification, the father said, “Cooper Flagg. He’s good.”

The Texas feel

Even if you don’t see many cowboy hats and boots on fans walking around, the arena has a clear Southwest flair.

There’s a Texas craft beer stand in one corner, while in another is the stand for ZiegenBock brewery, which markets itself as “The Great Taste of Texas.” In between, there’s a concession area for the Texas whiskey Balcones, another for barbecue, a Tostitos cantina and a taco stand.

Even away from the main walkways, the Texas feel is never far away. The media meal Friday night was chicken sandwiches, but the Saturday offering was fried catfish.

And during one of the timeouts Friday, the kiss cam or dance cam that has become a staple at stadiums, arenas and ballparks nationwide was replaced by a bull ridin’ cam — ridin’, not riding — in which fans waved an imaginary lasso while pretending to ride a bucking bull.

At that point, the Mavericks were trailing, and it was looking like a simulated bull ride was the most fun the fans were going to get.

The sounds of the game

The start of the game Friday had the makings of a rocking environment. Fireworks punctuated the player introductions, and the fans yell out “Stars!” when that word comes up in the national anthem, as a nod to the NHL’s Dallas Stars, who share the building.

For Mavericks fans, it’s routine. For Maine reporters there for the first time, it catches them off guard and almost makes them drop their drink.

This year, though, there’s been an addition: a full-throated “Flagg!” at “That our flag was still there.” On Friday, the camera caught the kid from Maine immediately afterward. Even after hearing it for the 13th time, Flagg couldn’t help but crack a smile.

As the game unfolded and New Orleans opened up a 15-point lead, however, the volume dropped. The drumline that plays after Mavericks baskets, giving the game a hint of a college feel, did little to rouse the fans, as did the PA announcer imploring them to get loud. Chants of “Let’s! Go! Mavs!” were only half-heartedly returned as Dallas fell behind 63-49 at halftime.

And then Flagg woke them up. There was a loud cheer when he backed down a defender and spun around before hitting a floater to make it 72-67. A louder cheer when he hit a twisting left-handed layup and drew a foul to bring Dallas with a point at 74-73. And an eruption that shook the building on the next series when Flagg drove for a thunderous dunk to give Dallas the lead.

Suddenly, it felt like a playoff game, with the 18-year-old in the middle of it. Fans rose out of their seats when a pass headed his way, eagerly awaiting what might happen next. And when he and the Mavericks continued the comeback, with Flagg scoring 12 points in the fourth, the volume only rose.

“He came out with a different mindset in the second half,” said Kidd, the Dallas coach. “And you could see the crowd respond to it.”

A reason for hope

Flagg’s become the player Mavericks fans, stung by the trade of superstar Luka Doncic and suffering through 5-14 start to the season, have clung to. Ever since the team took him first overall at the NBA Draft in June, he’s been looked to as the person who can turn a franchise reeling from a season of struggles back into a winner.

“All my buddies are Mavs fans, and they’re all fired up about Cooper. Everyone I know is fired up about Cooper,” said Carson Bridges, a fan from Paris, about an hour and a half northeast of Dallas. “Mavs fans that watched the 2011 team win a championship, they say we see in this kid someone (with whom) we can build toward another championship roster.”

And he’s become a player fans travel to see. One of them was Griffin Gullekson, a 16-year-old from Sparta, Michigan, who on Saturday was a Mavericks guest of honor. Gullekson is in remission after battling Stage 3 Hodgkin’s lymphoma, and he and his family got to meet the team before the game as part of an opportunity organized by the Make-a-Wish Foundation.

“It’s really exciting to see him lead a team like this,” Gullekson said. “I think it did ease the sting (of trading Doncic) a little bit. The more he develops, the more I feel like he’ll be able to lead this team way better.”

Gullekson got to chat and get autographs from Flagg before the game, as did his sister Natalie, who brought a large pink flag with a picture of Cooper from her room to the game.

“I was just so excited (when he got drafted),” said Natalie, 14. “I’ve been obsessed with Cooper for, like, two years. It’s kind of embarrassing, but I’ve got a really big crush on him.”

Mavericks fans are certainly falling for his game. Early in the third quarter Saturday, Flagg stood at the line for a pair of free throws. Fans typically go silent when their team’s players are shooting, but one child couldn’t resist.

“Cooper!” the faint, yet clear voice said. “You’re my faaavoriiiite!”

The kid has plenty of company.