"WWE extends its condolences to Patterson’s family and friends," the company said Wednesday in a statement.

Patterson -- who considered himself wrestling's "first gay superstar" -- was a key part of WWE for decades, widely known as Vince McMahon's right-hand man.

He began wrestling in the 1950s -- and finally joined up with WWE in the late '70s, where he famously engaged in a series of awesome matches with Sgt. Slaughter. Pat became the company's first Intercontinental Heavyweight Champion in 1979.

Patterson later became a color commentator for WWE -- and continued to work in the ring and in the booth until he retired in 1984.

At that point, Patterson joined McMahon as a WWE exec -- and in 1988, he pitched the idea for the Royal Rumble.

In his book -- "Accepted: How the First Gay Superstar Changed WWE" -- Patterson explained how the Rumble came to be.

"The first Royal Rumble was on January 24, 1988, in Hamilton, Ontario. The difference between WWE’s Royal Rumble and a traditional over-the-top rope battle royal is that the participants come into the match at two-minute intervals -- not all at the same time at the beginning of the match. I wanted to create something special."

Pat famously came out as gay during a 2014 episode of "WWE Legends House" ... opening up in front of guys like Roddy Piper and Jimmy Hart. It was a powerful moment.

Patterson was inducted into the WWE Hall of Fame in 1996.

RIP

The tributes are already pouring in ...

Vince McMahon -- "Pat Patterson was more than the first Intercontinental Champion & father of the Royal Rumble Match. He helped lay the foundation for WWE as we know it. His mentorship shaped careers, his creativity sparked innovation and his friendship lifted spirits. Love you, Pat. We miss you."

The Rock -- "Rough phone calls to get this morning to tell me, our dear family member, Pat Patterson who was my pro wrestling mentor and father figure has passed away."

"He was also responsible for calling Vince McMahon when I was training to become a pro wrestler (my $7 bucks days) and said, 'Vince you gotta see this kid work in the ring.'"

"Vince flew me to RAW a few weeks later and I had my first match EVER in Corpus Christie, Texas. The rest is history and years later, here I am writing this post."

Triple H -- "No words can describe what he gave to us. His body as an in-ring performer, his mind as a storyteller, and his spirit as a beloved member of our large WWE family. I will miss him for so many reasons ... it’s never goodbye, it’s see ya down the road. Love you, Pat. Abooze."

Shane McMahon -- "I can not express how crushed I feel right now with the loss of Pat Patterson. A true member of my family, mentor and dear friend. I love you Pat. God speed."

Jim Ross -- Just heard of the passing this morning if the great, Pat Patterson. True legend of the pro wrestling business.  A wonderful mentor who taught me so much. RIP old friend."