After news of the death of boxing great Marvin Hagler broke Saturday, tributes from around the combat sports world and beyond flooded in.

Among them, was UFC commentator Joe Rogan, who shared a 1983 sketch he drew of Marvin Hagler landing an uppercut on Tony Sibson. Rogan revealed he was 15 years old when he created the artwork.

“I remember watching a TV profile on him where he was running on the beach in the dead of winter shadow boxing and screaming ‘WAR!,” Rogan wrote in an Instagram post on Sunday.

At that age, Rogan was inspired by Hagler’s athletic mindset, performances, and feats. The inspiration still holds true present-day, Rogan said.

“They showed his maniacal dedication to training and fight preparation, and it had a massive influence on me,” Rogan said. “I would think of him when I was tired and was considering stopping. I would imagine what he would do and it would always fill me with energy.”

Like many boxing fans, Rogan was taken aback by Hagler’s death, but it opened the doors to reflecting and appreciating the boxing great’s best moments.

“When I heard he died yesterday I was stunned,” Rogan said. “I was such a massive fan all my life, and every now and then I’ll go to YouTube and watch some of his classic fights. The other day I watched his victory over Mugabi, and it was every bit as epic as I remembered. They don’t make many human beings as incredible as Marvin Hagler. He was truly one of the greats. RIP.”

Check out Rogan’s sketch in the tribute post below:

Hagler, a former middleweight champion, is considered one of the greatest boxers in history, a Hall of Famer known for his “Four Kings” series with Thomas Hearns, Sugar Ray Leonard and Roberto Duran.

Hagler’s April 1985 brawl with Hearns was an instant classic. Hagler won by third-round knockout after a frenetic first round that is still considered one of the wildest in boxing history.