By Victor Salazar

NEW YORK - Vasyl Lomachenko turned a Puerto Rican celebration into a Ukrainian holiday with a brutal knockout of Rocky Martinez to take the WBO junior lightweight title Saturday night.

On the eve of Puerto Rico Day, two-time Olympic gold medalist Lomachenko was dominant. Scoring with vicious left-handed leads, he connected on four straight, including a precise uppercut in the fifth round. Lomachenko followed that with a stunning right that flattened Martinez, who remained on the canvas for several moments.

"I came to do my job, I did my job very well tonight," Lomachenko said before dedicating the win to "the greatest man who ever laced up gloves, Muhammad Ali."

Lomachenko, 129 pounds, didn't exactly ruin the evening for the heavily Puerto Rican crowd that saw Felix Verdejo also scored a fifth-round knockout earlier. But he sure gave his loud if outnumbered countrymen in the crowd of 4,545 at the Theater at Madison Square Garden a thrill in improving to 6-1 as a pro with four knockouts.

He even did a back flip to punctuate the rout.

"I think anybody who follows boxing would see this performance and realize they have seen the birth of a superstar," promoter Bob Arum said.

Lomachenko won Olympic gold in 2008 and 2012 — he has tattoos honoring those victories on each bicep — and beat Gary Russell two years ago for the WBO featherweight crown. At 28, he is a rising star in Top Rank's stable, and HBO was eager to showcase him Saturday night.

The three-time world amateur champion is 28 and has come to the professional party late, but he's making the most of it.

Martinez, 33, fell to 29-3-2. He has held the WBO belt twice.