LOS ANGELES >> Coaches have notoriously big egos, but USC’s play-calling seems to be thriving with a unique system that requires teamwork throughout the game.

Offensive coordinator Tee Martin calls plays on first and second down. If third down is a passing situation, quarterbacks coach Tyson Helton calls the play while his brother, USC coach Clay Helton, offers input between drives.

This is unique, to say the least. Former USC coach Pete Carroll got so concerned about the glowing reputation of his offensive coordinator, Norm Chow, that Carroll started trying to help run the offense.

“I didn’t want recruits to think if Norm left that our offense would fall apart,” Carroll said.

Eventually, it led to Lane Kiffin and Steve Sarkisian pulling a mini-coup and convincing Carroll to take away play-calling from Chow, who went to the Tennessee Titans before it actually happened.

“I’ve been on a lot of unselfish and selfish staffs,” Tyson Helton said. “The reason we are successful is we are pulling together. There’s no question we are all team, all the time.”

It sounds easy, but does it really work? The reason it would is Clay Helton’s unassuming persona. He is not a self promoter and does not try to steal the credit.

He was a quiet, loyal assistant to Kiffin and Sarkisian. When Sarkisian made him the offensive coordinator, Helton was not allowed to call plays. And he never complained about it.

Few coaches are willing to stick around without some ego gratification. Kiffin and his offensive coordinator Kennedy Polamalu had a famous argument at the Sun Bowl, because Polamalu chafed at the lack of responsibility he was given. Kiffin refused to cede play-calling duties during his tenure at USC. Sarkisian only relinquished play-calling his second season when he saw he could not do everything by himself.

“(Clay) was unselfish and continued to do what was asked,” Tyson said. “It starts with the football coach. He’s an unselfish person. It’s about winning.”

Even with a three-headed monster, there is no arguing on the headsets during games, according to sources.

Just think back to a year ago, when defensive coordinator Justin Wilcox and his staff frequently got heated on the headsets during games with profanity and arguing. During one game, Helton reportedly had to tell the defensive assistants to settle down.

“There’s a lot of thoughts and communication (between us),” Tyson Helton said.

If the Heltons and Martin are low key, so is quarterback Sam Darnold.

The freshman also displays no ego and calmly handles everything, including broken plays, during games.

“I like to credit my coaches in high school and Pop Warner, but I think it comes down to my family and how I was raised,” Darnold said. “My parents did a good job keeping me confident and knowing that you just have to be cool with yourself.

“No matter what anyone else thinks you just have to control what you can control. You can’t control the past. You have to look ahead.”

It also helps to have Darnold’s athletic ability. But his special traits also make USC’s play-calling system work.

“Obviously, the quarterback is a good player,” Tyson Helton said. “It’s all about momentum.”

Right now, USC (6-3, 5-2) has plenty of it heading to Seattle to play No. 4-ranked Washington.

“I think it could be a defining moment for our whole team,” Darnold said. “We want to finish on high note and what would be better than beating No. 4 team in the nation.”