His chin is one of the best attributes Anthony Dirrell has displayed during his 14 years as a pro.

Dirrell’s durability and toughness have prevented any of his 35 opponents from knocking him out. David Benavidez believes that’s about to change.

The unbeaten challenger expects to stop Dirrell inside the distance when they fight for Dirrell’s WBC super middleweight title on the Errol Spence Jr.-Shawn Porter undercard September 28 at Staples Center in Los Angeles.

“I know I can hurt him,” Benavidez said during a conference call Monday. “I just know I can hurt him. You know what I mean? So, it’s not a matter of if I can hurt him, but it’s a matter of when I’m gonna hurt him.”

Phoenix’s Benavidez has knocked out 86 percent of his pro opponents (21-0, 18 KOs). The 34-year-old Dirrell (33-1-1, 24 KOs), of Flint, Michigan, is the best opponent, though, against whom Benavidez has been matched since the former WBC 168-pound champion turned pro at just 16 years old in August 2013.

“I feel like, you know, I’m 22 years old, but everybody sees my strength,” Benavidez said. “You know, they know I have good speed. You know, I’m very strong. I mean, I feel like with the confidence I have right now in my power, I feel like anybody who I hit, no matter who it is, you know, I’ll hurt them. You know, I’ve trained very hard for this fight. You know, I’ve had 3½ months. You know, I haven’t slacked on anything. My diet has been very good. My recovery has been very good. You know, my strength and conditioning has been excellent. So, all these factors have given me so much confidence in my abilities.”

Benavidez admits he has been driven during training camp by the thought of becoming the first foe to knock out Dirrell. He knocked out veteran J’Leon Love (24-3-1, 13 KOs, 1 NC) in the second round of his last fight, March 16 at AT&T Stadium in Arlington, Texas.

“And also, what gives me a lot of confidence is knowing Anthony Dirrell hasn’t been stopped, knowing that nobody’s knocked him out,” Benavidez said. “You know, so I wanna push myself to the absolute limit and do something that [nobody] has done. Anthony Dirrell’s never been hurt. He’s never been knocked out. So, you know, imagine what that’s gonna do for my confidence if I’m the only one that knocks Anthony Dirrell out, you know, if I knock him out in this fight.

“That’s what just keeps me going, because I know I can. I know whoever I put my hands on, I can hurt. It don’t matter who it is. I can do it in a variety of ways. I can do it from body shots. I can do it from head shots. I can do it from liver shots. I can do everything. You know what I mean? So, coming into this fight I know what I can do and who I’ve been there with. He has a lot of experience, but I also have a lot of experience, too. I’m 22 years old and I’ve been with the best of them almost seven years now. I’ve been in big fights. I’ve been in, you know, 12-round championship fights. I’ve fought some great contenders, so as much experience as he has, you know, I have as well.”

Keith Idec is a senior writer/columnist for BoxingScene.com. He can be reached on Twitter @Idecboxing.