Two quick drum beats. Thump, thump. Nermin Sakonjic yells into the bullhorn, “A.”

The Atlanta United crowd raises their arms above their heads, responds with an “A,” and then gives one big clap.

Two quick drum beats. Thump, thump. Sakonic yells for a “T.” The crowd responds.

The sequence is repeated with an "L," before the cheer repeats, "A," "T," "L," growing faster and louder with most of the 45,000 at Georgia Tech's Bobby Dodd Stadium following Sakonjic's lead.

It was a chill-inducing moment that the MLS expansion team’s players noticed even though they were supposed to be focused on the game against Chicago in March.

“The ground was shaking,” Atlanta United goalkeeper Alec Kann said. “That was pretty amazing.”

Sakonjic is one of two supporters, along with Michael Collier, who lead those in the lower level of the northern end of the Bobby Dodd in chants and cheers for Atlanta United. Collier and Sakonjic are called, “capos.”

Like a conductor, they stand above the crowd on a platform.

Like a conductor, they try to bring together a large group of people with one goal: to focus their energy and passion on influencing an event.

“I just want to create an atmosphere that’s seen all around the world,” Sakonjic said. “Each country and continent has a perfect atmosphere. There’s always one football team that creates the most perfect atmosphere. I want that for our supporters in MLS.”

Sakonjic and Collier take turns atop the platform in 15-minute shifts. There soon will be more capos rotating in.

Collier, a resident of Cartersville, became a capo because he is the music director for Terminus Legion, one of the team’s supporters groups.

“It kind of spiraled out of control from there,” he said.

He learned the role of capo by watching the American Outlaws, a supporters group for the U.S. men’s national team, and mimicking what their capos did. He also attended Silverbacks game and learned from those experiences.

“Nothing could prepare us for the 55,000 on March 5,” he said.

Collier was on the stand for the team’s first goal in the inaugural game against New York Red Bulls. He was so caught up in the moment he can’t remember what cheer he tried to lead to celebrate Yamil Asad’s historic score.

Sakonjic, a resident of Lawrenceville, was asked to lead cheers for the supporters group he belongs to, Resurgence. He learned the role of capo by watching those at Bosnia and Herzegovina games. His parents grew up in Bosnia and immigrated to the U.S. after the Bosnian War. When their nation’s team plays in the U.S., Sakonjic’s family typically attends.

Though Collier and Sakonjic know many more chants, and are constantly researching more, they typically choose from as many as 10 in a game. Because the team is new and the experience is new, they try to focus on simple chants that everyone can memorize and recite at a moment’s notice.

Collier said the different supporter’s groups keep an open line of communication and will meet before matches and during tailgates to go over chants.

Deciding which chant to use at what time is an interesting exercise. It’s not as easy as some in football and basketball because there are fewer moments with recognizable potential for drama or influence such as “miss that shot” in basketball, or “De-fense” in football.

“It’s a delicate balance of control and no control,” Collier said. “You don’t want to iron-will everything and force things to happen because then people won’t like you being up there.”

The “A-T-L” and Viking clap is about as simple a chant as there is, but it was memorable because of the volume and participation.

Sakonjic said he had tried the chant several times in the preseason and in the inaugural game, but it didn’t catch on.

During the game against Chicago, he noticed more people around the stadium were following the lead of those in the northern end of the stadium.

After the second goal, the crowd began to grow louder. Sakonjic said he could feel the energy in the stadium increasing. Like a good capo, he knew how to respond and what chant to use.

More than a month later, Atlanta United defender Leandro Gonzalez Pirez immediately knew what was being asked when he heard the phrase “Viking clap” used in a question.

“A-T-L?” he asked, and started smiling.

“That was one of the most amazing things I’ve seen in my life or been a part of,” Collier said. “I’ve been going to Georgia Tech games since I was a knee high, but I’ve never gotten chills like I had in that stadium until that day.

“Everybody was there supporting Atlanta United. Everybody had their hands up. It all started with the one drum.”