Roman Kopylov is one of many Russian fighters who came to the UFC intent on taking the promotion by storm. While his first two fights under the UFC banner led to him losing his undefeated record, the 32-year old middleweight has since bounced back with two wins, all finishes.Now, at UFC 291 this Saturday, Roman Kopylov is scheduled to face Claudio Ribeiro in a preliminary bout. The Russian will be hoping to defeat the Brazilian and extend his run to three consecutive victories. Meanwhile, Ribeiro just rebounded from a loss and is seeking his second straight win.MMA Orbit@mma_orbitRoman Kopylov will take on Claudio Ribeiro at #UFC291 on July 29.#UFC291 #UFC #MMA pic.twitter.com/l1Vft2eBbh16014Roman Kopylov will take on Claudio Ribeiro at #UFC291 on July 29.#UFC291 #UFC #MMA pic.twitter.com/l1Vft2eBbhThe Brazilian previously lost to knockout artist Abdul Razak Alhassan in January at UFC Fight Night 217. While Roman Kopylov entered the promotion to a lot of hype due to his undefeated record, all talk of him as a potential top contender came to an abrupt halt after he suffered his first loss at UFC Fight Night 163.But it was understandable. Before signing with the UFC, he was 8-0, with seven of his wins coming by way of knockout or TKO. Furthermore, he is a former FNG middleweight champion and WCSA middleweight champion. Unfortunately, his UFC debut couldn't have gone any worse.Not only did he lose, robbing him of his undefeated record, but he was finished with a rear-naked choke by Karl Roberson. Worse still, he was deducted a point in the last round after eyepoking his foe, albeit accidentally. To further punctuate the disheartening nature of his loss, Kopylov's defeat happened on home soil.Besides Roman Kopylov, who else lost their undefeated record in their UFC debut?Surprisingly, a man who is currently being discussed as a potential title challenger can relate to Roman Kopylov's initial situation in the UFC. Not only is he another Russian, but he was also a formerly undefeated power-puncher. Sergei Pavlovich was 12-0 ahead of his UFC debut, with nine wins via knockout or TKO.UFC on TNT Sports@ufcontnt"Demolition Man back in the win column!" Alistair Overeem hands Sergei Pavlovich his first loss in MMA with some vicious ground and pound at #UFCBeijing pic.twitter.com/6ynuNF3NQr26658"Demolition Man back in the win column!" 💪Alistair Overeem hands Sergei Pavlovich his first loss in MMA with some vicious ground and pound at #UFCBeijing pic.twitter.com/6ynuNF3NQrHe faced legendary heavyweight Alistair Overeem in his first bout in the promotion, losing via TKO in the first round. While it was a shocking loss, it forced Pavlovich to work even harder as he rebounded by amassing a six-fight win streak, finishing everyone in his path en route to enthroning himself as the #1 ranked heavyweight.