Jayhawk fans flood Massachusetts Street following Kansas' Elite Eight victory over North Carolina, Sunday, March 25, 2012 in downtown Lawrence.

The screaming had started before the game was over.

But when the last second finally ticked off the clock, the true pandemonium began. The sound of hundreds of horns honking blasted across the city. Bull horns resounded, stereos thumped and the Rock Chalk chant rang throughout the streets of downtown. People abandoned their seats in bars and restaurants to join the crowds on Massachusetts Street celebrating the 80-67 victory over the North Carolina Tar Heels.

Decked out in KU gear, Keith Hall, 21, dashed downtown from his house a few blocks away to participate in the mayhem. Hall was raised in Lawrence and has been a lifelong KU fan. He was in town when KU clinched the championship back in 2008, a night he recalls fondly.

“It’s hard to describe (if you’ve never experienced it),” said Hall. “It feels awesome. Everyone in Lawrence is here celebrating.”

Lauren Evrard, a KU junior, was overwhelmed with joy when it was clear that KU had won.

“I cried; it was the greatest feeling ever,” Evrard said. “I’ll be staying on Mass. Street tonight.”

Sam Gurney, 21, had never witnessed the sort of revelry that an Elite Eight win creates.

“I’m excited for the next couple of weeks,” he said. “If this is how it is for the Elite Eight, I don’t want to see what happens if they win the Final Four — well, I do, but you know what I mean.”

The high energy and excitement was palpable as some people scaled light poles, and others gave hugs and high-fives to random strangers passing by. Mike and Brenda Shirmer had left Kansas City, where they had started to watch the game, during halftime so they could watch the crowds in case of a win. With two children at KU, the Shirmers are a family of Jayhawk fans.

“It’s a lot of fun,” Brenda said. “The crowd is wild but controlled.”

At least six officers stood in a row in front of Esquina, 801 Mass., eyeing the crowd. But as the party went on late into the night, there were no game-related arrests, said Lawrence Police Capt. Bill Cory.

“The crowd’s been very positive, and our officers have a lot of good interactions with the public,” Cory said around 9:30 p.m. “It’s been a continuation of the positive attitudes we had in 2008. We just ask people to be responsible and have a good time.”

The open-container rule went into effect promptly at 6 p.m., allowing alcohol in plastic cups to be consumed on the streets.

Near the corner of Eighth and Massachusetts, David Garcia sat with a group of friends on the front of his GMC Yukon Denali. Each person clutched a transparent plastic cup filled with beer, the truck’s front door was open and Fatboy Slim’s “Praise You” blared from the stereo. “I’m going to sit out here, see what happens, high-five everybody and go home,” Garcia said.

To ensure KU won, Garcia and his roommate followed a set of superstitious rules: Garcia wore a different shirt for each game leading to the Elite Eight, while his roommate wore the same one. For the North Carolina game, both sat in the same seats they had been in when KU beat Purdue. And the flag that waves outside of their house has been there for two weeks now, for fear that changing it would cause KU’s luck to shift.

It looks like the flag will stay out front now.

“At the beginning of the season I said that if Bill Self gets the Big 12, I’ll be happy with that,” Garcia said. “But now, as a fan, we want more.”