Undefeated South African mixed martial arts talent Willie van Rooyen will fly his nation's flag high inside the ONE Championship Circle.The 23-year-old fighter, nicknamed 'White Lion', was announced as the world's largest martial arts organization's latest signing this past Wednesday, Oct. 15. ONE broke the news on its official site.Willie van Rooyen has been unstoppable since turning professional in 2023, bringing a high-octane style that guarantees non-stop action and pure chaos.He started his journey with a unanimous decision win over David Makane at EFC 107 in September 2023, after which the fighting pride of A-Team Stars in Pretoria, South Africa, has continued to rack up win after win.Van Rooyen's slate now stands at a perfect 7-0, and he enters the world's largest martial arts organization fresh off two wins in title matchups.He captured the EFC flyweight title this past May by landing a stiff straight right that shut down Brazil's Kleberson Sousa in a mere 37 seconds. Three months later, he overcame Moldovan slugger Anatolie Gafin via a rear-naked choke submission in Round 2.'White Lion' has finished five of his seven triumphs inside the distance, and he'll look to test his finishing acumen against the very best warriors on the ONE Championship roster. View this post on Instagram Instagram PostWillie van Rooyen locked in for debut fight at ONE Fight Night 37Willie van Rooyen will open his promotional account when he takes to the Circle against Uzbekistani sensation Avazbek Kholmirzaev at ONE Fight Night 37.Their scheduled three-round flyweight MMA matchup will go down in Bangkok, Thailand, live in U.S. primetime on Friday, Nov. 7.Like van Rooyen, the 24-year-old Uzbek slugger heads into this showdown in fine form.'Ninzya' has won seven of his eight assignments under the ONE spotlight, six of which have come by way of TKO and submission.With both men possessing the penchant to finish their fights, this one shouldn't go the distance.Can Willie van Rooyen debut in style, or will Kholmirzaev take away his "O" come ONE Fight Night 37: Kryklia vs. Agdeve? Let us know below!Active Amazon Prime Video subscribers in the United States and Canada can catch all the action live in U.S. primetime for free.