Demetrious “Mighty Mouse” Johnson, 36, is ONE Championship‘s new mixed martial arts champion in the flyweight division. The former flyweight champion of the Ultimate Fighting Championship is fighting out of Parkland, Pierce County, Washington, United States.

Johnson was born in Madisonville, Hopkins County, Kentucky, USA. He grew up in Parkland and went to Washington High School in Parkland where he made a mark as an outstanding athlete in wrestling, cross country and track.

The Madisonville native dethroned Adriano “Mikinho” Moraes, 34, of Brasilia, Federal District, Brazil in Singapore. The Brazilian MMA fighter held the ONE Flyweight World Championship title from September 12, 2014 to March 13, 2015, from July 5, 2017 to November 10, 2017 and from January 25, 2019 to August 27, 2022.

In 2007, Johnson made his professional MMA debut. In 2011, he joined the UFC.

From 2012 to 2017, John reigned as the UFC Flyweight Champion with 11 consecutive title defenses. He lost the title to Henry “Triple C” Cejudo, 35, of Phoenix, Arizona, USA on August 4, 2018 then made his ONE Championship debut on March 31, 2019.

On October 13, 2019, Johnson became the champion of ONE Championship’s flyweight grand prix, making him the first ever former UFC champion to win a ONE Championship belt. On April 7, 2021, he challenged Moraes, the then reigning ONE Flyweight World Champion, at “ONE on TNT 1” at the Singapore Indoor Stadium in Kallang, Central Region, Singapore.

Moraes knocked out Johnson at “ONE on TNT 1” via knee in the second round. The Brazilian MMA fighter did not have any title defense before their rematch at “ONE on Prime Video 1” at the Singapore Indoor Stadium on August 27, 2022.

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In the main event of “ONE on Prime Video 1”, Johnson knocked out Moraes via flying knee in the fourth round. The victory improved the professional MMA record of the fighter from Parkland to 31 wins, 4 losses and 1 draw.

Prior to “ONE on Prime Video 1”, Johnson submitted Rodtang “The Iron Man” Jitmuangnon, 25, of Bangkok, Thailand via rear-naked choke in the second round at “ONE Championship: X” at the Singapore Indoor Stadium on March 26, 2022. It was a special rules bout.