Nick Diaz has boldly claimed that he could beat UFC welterweight champion Kamaru Usman in a MMA fight. 

Diaz, 38, will return to the octagon this weekend as he goes up against Robbie Lawler at UFC 266 in Las Vegas.  

In a sit-down interview with ESPN's Brett Okamoto, Diaz was asked if he could beat reigning welterweight world champion Usman, who is coming off an impressive second-round knockout against Jorge Masvidal in April at the age of 33.

Despite spending an extended period of time on the sidelines, the 38-year-old made the incredibly bold claim that he should be fighting 'The Nigerian Nightmare' on Saturday night.

"I think I'll beat the s--- out of Usman," he replied.

"I'll have a better shot against Usman than I do Lawler, just because I already beat Lawler.

"This doesn't make sense for me to go in and fight Robbie Lawler again.

"I don't know why I'm doing this. This should not happen. Whoever set this up is an idiot.

"I don't know why I'm doing this. I don't know why this happened. I should be fighting Kamaru Usman - and that's it."

Diaz believes he will go 2-0 up against Lawler in their two-part series but expects to pick up a few bumps and bruises along the way.  

He added: "I'm going in there to win.

"Do I feel confident? I never do. I never have.

"I always feel like I'm going to get trashed out there. Every fight I've ever done.

"'How do you feel against Robbie Lawler?' I feel like I'm going to get the s--- beat out of me.

"And even when I win, I get beat up worse."

Diaz - who has previously spoken at great length about his struggles with mental health in the past - also admits he found it 'hard to watch' his younger brother Nate's fight with Leon Edwards at UFC 263 on June 12.   

"Being away for five years and coming back and seeing that, that was something new," Diaz said of Diaz vs Edwards in that same interview.

"It really kind of knocked my block off.

"I took harder punches watching that than I ever did in sparring or in any fights.

"It's my baby brother, you know? It's hard to watch him fight."

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