Vasyl Lomachenko takes care of Jason Sosa with a ninth-round TKO

Frustrated that he can’t get fights against the opponents he wants, Vasyl Lomachenko took his frustration out on Jason Sosa.

Lomachenko (8-1, 6 KOs) dominated his WBO junior featherweight title defense before Sosa’s own corner stopped the fight after the ninth round, completing a three-fight Ukrainian sweep on Saturday night.

After a bout in which even Sosa’s corner admitted they were the third choice, Lomachenko says he’s eager to unify titles.

Sosa (20-2-4) was a WBA belt holder at 130 pounds, but was forced to vacate to take this fight.

“I’ll go home, rest, and then I want to negotiate with all the other champions in my division,” Lomachenko said. “If they refuse to fight me, I’m going to move up to 135.”

Aleksandr Usyk (12-0) defended his WBO cruiserweight title with a 117-110 unanimous decision over Mike Hunter (12-1) in the first fight of an HBO TV card and the maiden boxing event at the MGM National Harbor.

And Oleksandr Gvozdyk (13-0, 11 KOs) won by a third-round technical knockout over Yuniesky Gonzalez to complete the Ukrainain sweep and unify the NABF and NABO light heavyweight belts.

In front of a heavy Ukrainian contingent in a sell-out crowd of 2,828, Lomachenko battered Sosa, who finished with a badly swollen left eye.

At one point in the sixth round, he mocked Sosa with a matador gesture, to the delight of fans who chanted his name and “Ooo-Cray-Nee-Ahh” throughout while waving blue and gold Ukrainian national flags.

By the ninth, it had become clear to Sosa’s corner that this was a no-win proposition.

“I couldn’t really execute,” Sosa said. “He’s a great fighter.”

That’s what many thought all along, and Lomachenko’s promoters would’ve rather seen a rematch with Orlando Salido or a unification bout with Jezreel Corrales.

Salido handed Lomachenko his only defeat in his second fight as a professional, but only after Salido failed to make the 126-pound weight limit.

“The first fight was like a 3rd-grader fighting a 12th-grader,” Lomechnko said. “I’ve now graduated to the university, and I want to invite Salido to my university.”

Earlier, Usyk appeared close to a knockout several times in the latter rounds of his bout.

In the 12th, he punched Hunter into the ropes and was awarded a knockdown from referee Bill Clancy. Hunter survived the round despite a brutal flurry from Usyk to close the fight.

“I did what I wanted to do,” Usyk said. “He took a lot of punches, I thought maybe they would stop the fight at the end.”

The theater at the MGM National Harbor doubled as a second home for the HBO card’s Ukrainian trio, from the moment hundreds in the crowd joined in the singing of their national anthem.

It continued all night, with national flags dotting the arena and the crowd chanting the names of all three fighters’ names during their respective bouts.

sports@latimes.com