SPRINGFIELD, Mass. — At a certain point, the capacity crowd at the Hoophall Classic stopped moving. The spectators stopped trying to push and squeeze and “Excuse me, sorry” their way into better vantage points or a rare pocket of open space. They had no choice but to stay where they were and enjoy the show.

In truth, the midday Monday slate at Hoophall, a national showcase event put on by the Naismith Memorial Basketball Hall of Fame, deserved a bigger stage than Springfield College’s Blake Arena. The aging venue can hold 2,500 and has done so many times in its 19 years hosting this event. But the fervor surrounding this year’s lineup was fresh and relentless. For the first time in Hoophall history, all three days of national boys’ games had sold out in advance.

Monday’s tickets were the first to go, mostly because of the lunchtime doubleheader. Evan Mobley, the nation’s No. 1 player out of Rancho Christian (Calif.), would face DeMatha at 11 a.m. and Sierra Canyon (Calif.), the traveling basketball circus featuring Bronny James and Zaire Wade, was set to take on Paul VI at 1 p.m.

“We’ve played in gyms where it was just electric before. And this is our fifth time here. But I walked out there and said, ‘Whoa.’ It was just a different energy,” Paul VI Coach Glenn Farello said.

By halftime of DeMatha’s 72-65 win, walking around the arena was difficult, and there was a rumor spreading that LeBron James, whose Los Angeles Lakers were set to visit the Boston Celtics on Monday night, was going to make the 90-minute trip to Springfield to see his son play. As the Stags put the finishing touches on their second win of the weekend, the public address announcer repeatedly asked the crowd to squeeze in.

“Every seat in this building will be filled,” he emphasized.

A few minutes before tip-off, the LeBron rumors became reality. His entrance created a racket in the gym, and the buzz that followed the bang lasted until he left. Fans talked to him in the silence of every free throw and stared his way in the calm of every break.

Paul VI, already prepared for the type of environment that follows Sierra Canyon everywhere, now had one more spectator to impress.

“It’s definitely shocking. It’s a surreal moment when you see him sitting there,” Panthers guard Jeremy Roach said. “You know you just have to be great.”

The Panthers had arrived in Springfield, Mass., straight from Springfield, Mo. They had played three games at the Bass Pro Shops Tournament of Champions, one of the few midseason national events that rivals Hoophall. But the Panthers showed no jet lag early, when Sierra Canyon wanted to run and they gladly obliged. An up-tempo team featuring more than one elite guard, Paul VI has the speed to motor past just about any program in the country.

Even the Panthers’ young players looked comfortable despite the size — and celebrity status — of the crowd. For anybody that went tumbling past the hoop on a drive or loose ball, they either crashed into LeBron’s section or ran headlong into a horde of Division I coaches stationed under the opposite basket.

“I expected the environment to be packed and all eyes would be on us,” sophomore guard Dug McDaniel said. “Just had to block out the distractions.”

Bronny James played sparingly for the Trailblazers, going scoreless in 13 minutes. Wade sat out with an injury, and Sierra Canyon struggled to contain Paul VI’s guards in the second half. Paul VI junior guard Trevor Keels, who finished with 24 points and earned team MVP honors, made a three-pointer with two minutes left to put his team up five.

On the next play, Roach gathered a loose ball and was joined only by Keels and McDaniel on a breakaway. The senior rose up for a one-handed jam as his teammates celebrated. The crowd roared. Maybe some of them had come to cheer on California’s main attraction, but by that point Paul VI had officially stolen the show. The Panthers would go on to win, 70-62.

“Our guys had a chip on their shoulder because the whole story has always been that it’s [Sierra Canyon’s] show and, ‘Oh, by the way, who are they playing?’ ” Farello said. “Our team said, ‘Hold on — we’re pretty good, too.’ ”

It wasn’t just Paul VI that made a statement. The Washington Catholic Athletic Conference as a whole planted its flag on a slate filled with some of best and buzziest programs in the country, going 3-0 in Monday’s action.

Before DeMatha took down Rancho Christian and Paul VI beat Sierra Canyon, O’Connell began the day with a 73-72 win over California powerhouse Mater Dei. Junior Wes Peterson Jr. drew a foul with 0.9 seconds remaining and made the second of two free throws to hand the Knights, who have hovered around .500 in a rebuilding year, a major upset over the Monarchs.

“We just proved that we’re the best conference in the world,” Keels said after the third victory was complete. “We let everyone know.”