A 27-year-old American's head kick was so powerful it left his opponent stiff and unconscious before he hit the floor at UFC 244

Photo by Josh Hedges/Zuffa LLC via Getty Images

Kevin Lee after defeating Gregor Gillespie at UFC 244.

• Kevin Lee's brutal head kick left his Saturday opponent stiff and unconscious for more than a minute.
• Lee had suffered two successive losses before UFC 244, but bounced back with a highlight-reel finish, knocking out Gregor Gillespie in style at Madison Square Garden in New York City.
• "This is a new resurgence in my career," Lee told ESPN post-fight.
• Watch the leg kick knockout right here.
• Visit Business Insider's homepage for more stories.

Kevin Lee's head kick was so powerful it left his opponent stiff, unconscious, and on the floor at UFC 244. The knockout was so nasty, the UFC rewarded Lee with a $50,000 bonus, MMA Junkie reports.

It is a massive turnaround in fortunes for the 27-year-old American because Lee had been written off after back-to-back losses to Al Iaquinta and Rafael dos Anjos in the last 12 months, but produced a highlight-reel knockout by defeating Gregor Gillespie in style on Saturday.

It all happened midway through the first round of their lightweight fight at Madison Square Garden in New York City.

Lee staggered Gillespie with a thudding overhand right then followed up with a left-footed head kick that separated his opponent from his senses as soon as it landed on his chin.

Gillespie was unconscious before he hit the canvas, but Lee hit him with afters anyway, sending a right-handed hammer fist down on the beaten New Yorker's face before the referee tackled Lee to protect Gillespie.

Watch it here:

Or here if you're in a different region:

"When you come out and do what Kevin Lee did tonight … people are talking about Kevin Lee," the UFC boss Dana White said in a media scrum, according to BT Sport. "I'm talking about Kevin Lee. You guys are going to talk about Kevin Lee. Fans are talking about Kevin Lee.

"Kevin Lee came out and, you know, biggest show ever, the president of the United States was watching, The Rock was out there … and he went out there and did what you're supposed to do, on a night like tonight."

Lee's record moves to 18 wins (three by knockout and eight by submission) against five losses.

"I can bring a lot that people just ain't seen from me yet," Lee told the ESPN reporter Brett Okamoto after UFC 244. "This is a new resurgence in my career. I wanted to remind everybody who the future is in this division.

"It's amazing … fighting in front of the president of the United States. I felt like I got that job done," Lee said. 

Read more:

Jorge Masvidal called Donald Trump a 'bad mother f-----' and the president responded by saying: 'Great fight, champ!'

UFC boss Dana White says there won't be an immediate rematch between Masvidal and Nate Diaz because Jorge was so dominant

Jorge Masvidal drank liquor, ate pizza, and dissed Conor McGregor in his post-fight press conference after dominating Nate Diaz

Jorge Masvidal opens Nate Diaz up with bloody cuts, wins 'baddest mother f-----' title, then celebrates with The Rock

Saul 'Canelo' Alvarez hit Sergey Kovalev with a knockout punch so hard the Russian collapsed through the ropes