Kamaru Usman will make his middleweight debut at UFC 294 in Abu Dhabi after the former welterweight champion stepped in last minute to face unbeaten Khamzat Chimaev, UFC president Dana White announced on Wednesday evening. Usman (20-3) was one of the most dominant welterweight champions in UFC history, successfully defending the title five times after claiming the belt against Tyron Woodley at UFC 235 in March 2019. However, the 'Nigerian Nightmare' is <a href="https://www.thenationalnews.com/sport/2023/03/19/leon-edwards-retains-welterweight-title-with-points-win-over-kamaru-usman-at-ufc-286/" target="_blank">coming off successive losses</a> to current champion Leon Edwards, the most recent in March, and will make the step up to the heavier division for the first time. Usman's opportunity came after Chimaev's original opponent, Paulo Costa, withdrew due to injury. Chimaev, unbeaten after 12 professional fights, is the UFC's No 4-ranked welterweight but has previously fought at middleweight. UFC 294 will mark his return to the octagon since last fighting in September last year. It is the second time in as many days the UFC have had to draft in new opponents for the fight night in Abu Dhabi. Former lightweight champion Charles Oliveira <a href="https://www.thenationalnews.com/sport/combat-sports/2023/10/11/ufc-294-volkanovski-to-face-makhachev-in-abu-dhabi-after-oliveira-withdraws-with-injury/" target="_blank">withdrew from his rematch bout</a> with title holder Islam Makhachev on Monday after sustaining an injury in sparring and has been replaced by featherweight king Alexander Volkanovski. “You know what we’ve been dealing with this week. We just got the big fight done yesterday, the highly anticipated rematch in Abu Dhabi: Makhachev vs Volkanovski,” White said. “Now you’ve been waiting for the co-main event. Costa’s hurt … we got it done. The No 4 welterweight in the world, Khamzat Chimaev, is moving up to middleweight and he will face the No 1 welterweight in the world: Kamaru Usman. “No 1 vs No 4 at middleweight, Usman vs Chimaev,” White added. “I will see you in Abu Dhabi!” Both fighters have experience fighting in Abu Dhabi, Usman making the second defence of his welterweight title with a <a href="https://www.thenationalnews.com/sport/other-sport/ufc-251-kamaru-usman-beats-jorge-masvidal-to-retain-title-in-abu-dhabi-1.1047881" target="_blank">unanimous points win over Jorge Masvidal</a> at UFC 251 in July 2020. Chimaev, meanwhile, has competed in the capital on three previous occasions with the UFC, his first two appearances setting a new UFC record for the quickest turnaround between fights. After marking his UFC debut with a second-round submission of John Phillips on July 16, 2020, Chimaev returned to the octagon 10 days later to defeat Rhys McKee with a first-round stoppage at welterweight. The co-main event is part of an exciting card at Abu Dhabi's Etihad Arena, which will also see history being made as Mohammed Yahya <a href="https://www.thenationalnews.com/sport/combat-sports/2023/09/11/mohammed-yahya-to-make-history-as-first-emirati-to-fight-in-ufc/">becomes the first Emirati to fight in the UFC</a> when he enters the octagon against American Trevor Peek at lightweight. Other notable bouts include a clash of middleweight contenders in Nassourdine Imavov and Ikram Aliskerov, while former light-heavyweight title challenger Magomed Ankalaev takes on Johnny Walker, and <a href="https://www.thenationalnews.com/sport/ufc/2022/10/22/ufc-280-muhammad-mokaev-dominates-malcolm-gordon-in-abu-dhabi/">top prospect Muhammad Mokaev</a> meets Tim Elliott at flyweight.