Derrick Lewis is the UFC's new heavyweight knockout king.

"The Black Beast" stopped Aleksei Oleinik via TKO at :21 of the second round on Saturday in the main event of UFC Fight Night in Las Vegas. With the stoppage, Lewis earned his record 11th UFC heavyweight KO/TKO, breaking a tie with former champions Cain Velasquez and Junior dos Santos. That KO/TKO mark also puts Lewis in a tie for second with four others for the most knockouts in UFC history.

Lewis came out of the corner in the second with a wild flying knee that landed to Oleinik's chest. Lewis then quickly uncorked a winging right hand that landed flush on Oleinik's jaw.

Oleinik fell, and Lewis poured it on with hard punches and hammerfists. Referee Herb Dean had no choice but to step in and call the bout via technical knockout.

"It's crazy. I still can't believe that I've got the most knockouts," Lewis said in his postfight news conference. "It's a crazy feeling because of all the great heavyweights before me. ... Watching Brock Lesnar and Cain Velasquez, all those guys for all those years. Seeing they didn't accomplish what I did, I've just gotta stay humble about it."

The card took place in front of no fans at the UFC Apex, the facility across the street from the UFC's corporate campus, with COVID-19 protocols in effect. Coming in, Lewis was ranked No. 6 in the world at heavyweight by ESPN, and the bout had significant implications for the top of the division.

Oleinik, a submission specialist, had a solid first round. After Lewis took him down -- perhaps unwisely -- Oleinik was able to get into dominant position twice, attempting an old-school scarf hold. Oleinik locked his arms around Lewis' head and arm from side control and squeezed. Oleinik could not fully cinch it, though, and gave up on it, moving to an Americana submission attempt on Lewis' arm. Lewis was able to survive the round.

"He had that British bulldog, whatever the hell -- that head submission on me," Lewis said in his postfight interview. "He had it pretty deep. I couldn't breathe at all. So, s---."

Despite Oleinik's solid submission attempts, Lewis was awarded the first round by judges Chris Lee and Sal D'Amato, likely because he did more damage with his striking. Judge Derek Cleary had the first for Oleinik.

Lewis said he won't take another fight until he is able to drop down into the 245- to 250-pound range. Lewis typically comes in right at the 265-pound heavyweight limit. He said he is hoping to lose some weight and come back in December.

"I'm not gonna take no more fights at 260," Lewis said.

Lewis (24-7, 1 NC) has won three straight and six of his past eight fights. The Houston resident lost to Daniel Cormier in a heavyweight title fight at UFC 230 in November 2018 at Madison Square Garden, but he has now worked his way back into the title picture. Lewis, 35, is now tied for third for the most wins in UFC heavyweight history with dos Santos (15).

Oleinik (59-14-1) had a two-fight winning streak snapped. The Ukraine native, who lives and trains in Florida, was coming off a split decision victory over former champion Fabricio Werdum at UFC 249 in March.

Oleinik, 43, is one of the top heavyweight grapplers in MMA history, with 46 submission finishes in his 59 career wins.

He also is one of the most seasoned veterans in the game. Oleinik, who has been a pro for 24 years, became the first UFC fighter to fight in MMA -- and win in MMA -- in four different decades earlier this year.