It was somewhat frustrating for Erickson Lubin to watch Jermell Charlo and Brian Castano fight to a split draw July 17 in San Antonio.

Three weeks earlier, Lubin knocked out former IBF/IBO/WBA 154-pound champion Jeison Rosario in the sixth round of what was considered a very risky fight for a contender who clearly has been willing to fight anyone while attempting to rebuild his career following a devastating defeat to Charlo in October 2017. Lubin believed he would get the Charlo-Castano winner next, but their draw necessitated a second title unification bout between them May 14 and left Lubin to take yet another difficult fight against Sebastian Fundora.

Lubin (24-1, 17 KOs), of Orlando, Florida, and Fundura (18-0-1, 12 KOs), of Coachella, California, will fight for the WBC interim super welterweight title Saturday night. Showtime will broadcast Lubin-Fundora, a 12-round battle between southpaws, as the main event of a tripleheader scheduled to start at 10 p.m. ET from Virgin Hotels Las Vegas.

The 24-year-old Lubin feels like he is in the same position as when he boxed Rosario – if he wins, he’ll fight whoever emerges victorious from the Charlo-Castano rematch next. Houston’s Charlo (34-1-1, 18 KOs) and Argentina’s Castano (17-0-2, 12 KOs) will square off a second time for Charlo’s IBF, WBA and WBC belts and Castano’s WBO title in another “Showtime Championship Boxing” main event next month from Dignity Health Sports Park in Carson, California.

“I feel like I’m number one in line, honestly, for the titles, for the winner of Charlo-Castano,” Lubin told BoxingScene.com. “I feel like I worked my way back. I felt like after the Rosario fight, I was next in line. But due to them having a draw and me not wanting to be inactive, I’ll take the next best in line, and that’s Sebastian Fundora, honestly. He’s been doing his thing, so I felt like since the WBC ordered it, let’s make it happen.”

Lubin has won six straight fights since Charlo knocked him out with one punch in the first round nearly 4½ years ago at Barclays Center in Brooklyn.

The strong southpaw withstood some adversity versus Rosario. The Dominican Republic’s Rosario (22-3-1, 16 KOs) buzzed Lubin with left hand toward the end of the third round, but Lubin recovered and came back to drop Rosario twice during the sixth round, when their scheduled 12-round WBC elimination match ended on the Gervonta Davis-Mario Barrios undercard June 26 at State Farm Arena in Atlanta.

“I feel like that fight, I just [showed] I can overcome whatever, honestly,” Lubin said. “Fighting Rosario, you know, he’s a real strong fighter. He beat J-Rock [Julian Williams]. He knocked J-Rock out. And he actually gave Jermell some hell for a few rounds, before Charlo ended up stopping him. But I feel like what people could take away from that fight with me is it’s just like I’ve got it all. I could box, I could bang. If you don’t see it, I’m just gonna have to continue to show. I feel like I can do it all in the ring. It doesn’t matter who’s in front of me.”

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