Brian Castano didn’t need any more motivation heading into his second straight bout with Jermell Charlo.

Far be it from his bitter rival to not provide some for him, anyway.

The undisputed junior middleweight championship rematch comes with plenty of bad blood after Argentina’s Castano (17-0-2, 12KOs) and Houston’s Charlo (34-1-1, 18KOs) fought to a disputed twelve-round draw last July in San Antonio, Texas. Several delays were met with getting the two back into the ring, including a slight biceps tear suffered by Castano in having to withdraw from a scheduled March 19 date at Arena in Los Angeles.

Charlo—the reigning lineal/WBC/WBA/IBF champ—went as far as to accuse Castano of faking the injury and even trying to stall random drug testing protocols until he was in a better position to defend his WBO title. As the fight draws nearer—taking place this Saturday on Showtime from Dignity Health Sports Park in Carson, California—Castano has plenty of ammunition to finish what he started nearly a year ago.

“Did it bother me? Yes. Did it surprise me? No,” Castano said of Charlo’s speculation over the unbeaten Argentinean faking his injury. “He’s just trying to mask his own insecurities. What bothered me was the lack of respect for a colleague.

“The first fight was close. The rematch will be even worse because I’m going to knock him out.”

Most observers felt Castano did enough to have deserved the victory in their four-belt unification bout last summer. Judge Steve Weisfeld (114-113) turned in the only scorecard in favor of Castano, who somehow managed to lose nine of the twelve rounds in the eyes of judge Nelson Vazquez (117-111, Charlo). Judge Tim Cheatham (114-114) had it even, thus producing the split decision draw.

Efforts to run it back saw dates pushed back from February to March and now to May. Charlo insists that Castano was merely trying to buy time to get down to the 154-pound divisional limit. Castano had to provide medical proof of injury to the WBO just to keep his title reign intact. In his view, an explanation isn’t required for his opponent though he’s happy to do plenty of talking in the ring this Saturday.   

“You can believe what you want about my injury,” Castano told Charlo. “What bothers me, you’re talking shit and I don’t appreciate it. I don’t need drugs to cheat, I don’t need more time to face you. I did my job last time and I’ll do it again.”

Castano attempts the second defense of his WBO title he claimed in a twelve-round, unanimous decision victory over Patrick Teixeira last February. Charlo aims for his third overall title defense of his second WBC title reign and his second as a unified titlist.

Jake Donovan is a senior writer for Twitter: @JakeNDaBox