Like a true big brother, Arizona Cardinals cornerback Patrick Peterson will politely remind you that it’s pronounced TY-run.

“He hates when people call him TY-ron,” he says.

Because you don’t disrespect Tyrann Mathieu, the Cardinals superstar safety and Peterson’s best friend, the other little brother he always wanted.

“I have one biological baby brother and I always wanted another, but my mom ended up having three girls after us,” says Peterson. “The bond that we have is special.”

It’s the first week of Cardinals training camp in Glendale and Peterson, 26, is remembering the first time he met Mathieu, 24, and describing how both of them have been there for each other for the past seven years. It started in college at LSU in 2009, and it’s continued in the NFL where they star in the Cardinals’ secondary. Two supremely talented players, with two disparate personalities, who compete and elevate each other to new levels, sharing a bond they struggle to put into words.

“We just click,” says Mathieu. “I’ve been trying to describe it for six years—it’s hard.”