Riggs admits he's getting close to the end of his career, but he wants one more opportunity to duke it out with Diaz.
"I would beat him again, 100 percent," Riggs said of Diaz. "Absolutely I would beat Nick again, that would be a fun fight, we have gone 18 fights after that and I think stylistically, styles make fights. I kind of wrote the book on how to beat him. You can't get that guy to go backward, you have to counter punch him, and he is very easy to counter punch."
Unfortunately for fight fans, Riggs vs Diaz isn't likely to happen any time soon because the men are fighting for rival promotions.
Riggs is currently competing under the Bellator umbrella, and Diaz was last seen in action in the UFC.
Riggs, who fights on Bellator's Nov. 2 card, says he wants to make one last run at the title before hanging up the gloves for good.
Riggs says he still has the tools to compete inside the cage, but there are other things he's interested in doing.
"I'm at the end of my career," Riggs said. "Not because I can't compete, but there are other things I want to do in life. I want to make one more run at the title and then hang them up. It could take one year, it could take five.
"I think it's obvious when a fighter has had too much, he doesn't have the chin he used to, there are a lot of signs, for instance Phil Baroni should have retired several years ago, but that goes for a lot of fighters, they attach their whole identity to fighting, it's hard for them to let go. I think fighters need to have someone in their camp to step up and tell them 'it's time to let go.' Even the commission has a responsibility. Look at Chuck Liddell, at one time he was invincible and then at the end it was gone. There is a shelf life on MMA careers."
Riggs fights Mike Bronzoulis on Nov. 2, as part of Bellator's MMA card on Spike TV.