WBO featherweight champion Shakur Stevenson only needed six rounds to see off Felix Caraballo in their non-title bout in Las Vegas.
The MGM Grand Convention Centre played host to boxing's return in the US with no fans present due to coronavirus.
Stevenson, now 14-0, almost had the Puerto Rican out in the first round when a left hand to the body forced Caraballo onto one knee.
The 22-year-old southpaw dominated throughout and when Stevenson dropped his 33-year-old opponent with another body shot in the sixth round, referee Tony Weeks stepped in to wave the fight off.
It was an eighth knockout of his professional career for the silver medallist at the Rio Olympics and the impact of the punches could be heard clearly in the empty venue.
Stevenson was later taken to hospital after hurting his right hand in the fifth round but he was confident it was not broken.
"He opened up wide and I caught him between his punch, caught him right in the middle of the shot," Stevenson said.
"I came here to get him out of there. I hit him with everything I could early. I wobbled him a bunch of times. He took a lot of punishment and I started wondering whether the head shots weren't going to get him out of there so I started going to the body."
Stevenson also talked about how different the build up to the fight as well as what it was like to fight without any fans inside the venue.
"It's a different atmosphere. Losing the weight was different, training was different," Stevenson said.
"I couldn't be around nobody and even fighting without a crowd where you catch him with a shot and don't hear oohs and ahhs is different."
Stevenson wore a Black Lives Matter t-shirt during his post-fight interview as protests continue across the US following the death of George Floyd.
"Our people right now, they are protesting and there is a lot going on in my community," Stevenson said.
"A lot of people are trying to stand up for what's right. I couldn't really go out there and protest with them because I had a fight coming up, but now that the fight is over, I can go out there and protest and show love to my people and lift them up."
Among the other fights on the undercard in Las Vegas, Guido Vianello stopped Donald Haynesworth in the first round and Robeisy Ramirez, who beat Stevenson to bantamweight gold at the 2016 Olympics, also finished Yeuri Andujar in the opening round.
