Sebastian Fundora retained the unified WBC and WBO junior middleweight titles with a fourth-round TKO of Chordale Booker on Saturday in Las Vegas.

Fundora (22-1-1, 15 KOs) is boxing’s tallest champion at 6-foot-5½ despite weighing just 154 pounds. He used his 8½-inch height advantage to apply pressure behind his long southpaw jab as he bloodied Booker.

Fundora stunned Booker in Round 3 and then floored the challenger the following round with a series of shots. Booker tried to survive, but a flurry of punches along the ropes forced the referee to halt the fight with nine seconds remaining in Round 4.

“He was moving a lot; I don’t think he wanted to trade at all,” Fundora, 27, said.

Fundora’s return after a career-long one-year layoff amounted to a stay-busy fight. Fundora was lined up for a fight with former champion Errol Spence that was planned for October 2024 but was delayed numerous times and finally canceled from its March 29 date.

Fundora should be lined up for a far more compelling fight this summer. Undefeated Puerto Rican Xander Zayas is Fundora’s mandatory opponent for both belts and could be next. Fundora also mentioned a possible unification with IBF champion Bakhram Murtazaliev.

Fundora, who fights out of Coachella, California, is ESPN’s No. 2 junior middleweight. He won the titles last March when he defeated Tim Tszyu in a split-decision upset in one of the year’s best action fights. Fundora accepted that assignment on 11 days’ notice after Keith Thurman was injured.

Known as “The Towering Inferno,” Fundora has an 80-inch reach and is ranked No. 2 at 154 pounds by ESPN. Fundora and his sister Gabriela are the first brother and sister to be full-fledged champions in boxing history. She was named ESPN’s 2024 Women’s Fighter of the Year.

Booker (23-2, 11 KOs) had won six consecutive fights since a first-round KO loss to Ammo Williams in 2022. The 33-year-old, who fights out of Stamford, Connecticut, was vying for his first world title.