Shakur Stevenson remains unbeaten as a professional boxer, defeating Jeremiah Nakathila by unanimous decision but even the victor was unhappy with the quality of the fight. 

Stevenson – the 2016 Olympic silver medallist – improved to 16-0 after the American claimed the WBO interim junior lightweight title in Las Vegas on Saturday.

A former WBO featherweight champion, Stevenson won 120-107 on all three judges' scorecards, though he acknowledged he was far from his best. 

"I apologise to all my fans I didn’t feel good tonight but I did what I had to do to win," Stevenson – who scored a knockdown of Nakathila (21-2) in the fourth round – tweeted after the bout. 

"Thank you for all da support I promise better for further fights to come."

The crowd in Las Vegas showered the fighters in boos in the 11th round as the 23-year-old Stevenson and his Namibian opponent Nakathila wrapped up an uninspiring affair.

"To be honest, I didn't really like my performance. I felt I could've performed a lot better," Stevenson said. "You had an awkward fighter throwing hard punches, and he knows how to grab and get away. He was a real awkward fighter.

"I tried to get him out of there a little bit, but I started getting hit with some solid shots. I ain't really like it, but next time I'm going to work on moving my head a little bit more and step it up a little more."

Stevenson is now set to face fellow WBO junior lightweight champion Jamel Herring (23-2) later this year. 

"If I had the choice, I'd take Oscar Valdez, but if I have to beat up Jamel to get to it, I'll do that, too," Stevenson said. "Jamel can't beat me. He knows what it is."