Jermall Charlo outlasted Sergiy Derevyanchenko via unanimous decision to retain his WBC middleweight title, while twin brother Jermell became unified world junior middleweight champion.
Identical twins Jermall and Jermell headlined Saturday's main events at the Mohegan Sun Arena in Uncasville, Connecticut.
In the first bout, Jermall Charlo overcame Derevyanchenko over 12 rounds, with all three judges scoring the fight 116-112, 117-111 and 118-110 in favour of the American.
"I made my team proud and I did what I was supposed to do," said Jermall, who improved to 31-0. "I executed the game plan. [Trainer] Ronnie Shields told me that I passed the test tonight. I'm happy to go back to the drawing board now and figure out what's next.
"He was tough, but I knew he was going to be tough. I knew he'd come to fight, I just didn't know how and when he'd try to turn it up. I felt like I never really let him turn it up and that was the game plan.
"I studied well and I didn't let the pandemic affect my training. I just want to keep fighting and not let any negative interrupt the positive."
And Jermell Charlo capped a clean sweet after his brutal eighth-round knockout of Jeison Rosario in the second fight.
Jermell (34-1) struck Rosario in the stomach with a powerful jab, flooring the Dominican boxer in the eighth round and he failed to make the count.
With the win, Jermell snatched the WBA and IBF junior middleweight titles and added them to his WBC strap.
"Dreams do come true and I believe this is part of my dream and part of my destiny," Jermell said. "My twin brother is excited. We're going to go do our bubble turn-up. He's my biggest fan. I love him to death.
"We're getting ready to take over," he added. "We're the new era of boxing."