By Keith Idec

NEW YORK – Keith Thurman thinks the differences in their performances against Julio Diaz are indicative of the advantages he owns over Shawn Porter.

Thurman stopped a faded Diaz after two rounds two years ago in Carson, California. Porter soundly defeated Diaz in their rematch in September 2013, but only after they fought to a 10-round draw in their first fight 3½ years ago.

Porter doesn’t consider Thurman’s dominance against Diaz any kind of advantage for Thurman (26-0, 22 KOs), whom Porter (26-1-1, 16 KOs) will challenge Saturday night for the WBA welterweight title at Brooklyn’s Barclays Center (CBS; 9 p.m. ET/6 p.m. PT).

“I don’t think it is,” Porter said. “When I fought Diaz, he was, to that point and still is, one of the best fighters I’ve ever fought against as an amateur and pro. The second time that I fought him it was about staying focused and taking care of business, doing things the way I need to do them. And I think that’s why I was able to dominate him the way I was. After that, he fought Amir [Khan] after me, I believe. And then he fought Keith, so he was about done.”

Diaz (40-10-1, 29 KOs), of Coachella, California, surprised Porter with his durability during their first fight, contested in December 2012 at Staples Center in Los Angeles. Judge Marty Denkin scored that bout for Diaz (96-94), but Steve Morrow scored it, 96-94, for Porter and Barry Druxman had it even (95-95).

Porter, of Akron, Ohio, won their 10-round rematch on all three scorecards (98-92, 97-93, 97-93) nearly nine months later in Las Vegas. Thurman, meanwhile, hit Diaz with a body shot that caused a rib injury and led to their scheduled 12-round fight ending between the second and third rounds in April 2014.

“To be honest with you,” Porter said, “he was supposed to be a [steppingstone] for me the first time that I fought him. He ended up being much more than that. I was able to prove some things to myself in fighting him again. … When he fought Keith, he was at the end. And he didn’t even quit. His team threw in that towel.”

The Thurman-Porter showdown will headline CBS’ first prime-time boxing telecast since Leon Spinks upset Muhammad Ali by split decision to win the WBA and WBC heavyweight titles in February 1978.

Keith Idec covers boxing for The Record and Herald News, of Woodland Park, N.J., and krikya360.com. He can be reached on Twitter @Idecboxing.