Roberto ‘Satoshi’ de Souza just rattled off his fifth straight title defense by submitting Yoshinori Horie at RIZIN 51 on September 28th, 2025. He’s been the RIZIN FF lightweight champion since 2021, so he’s on both the longest title-reign and most defenses in the promotion’s history. He was a heavy favorite coming into the fight and although Horie is a veteran fighter with solid striking, Satoshi’s elite grappling was predicted to win the fight. That’s pretty much exactly what happened when they entered the ring too, as it took him just one minute and forty seconds to find Horie’s back and finish the choke from a standing position.
With such a quick finish, Satoshi has sustained very little damage and could jump back in to action fairly soon. In fact, Satoshi has had 5 fights since the beginning of 2024 and he’s finished all of them in less than 10 minutes of total fight-time. He’s known for being a fast starter and he’s finished the vast majority of his fights in the first round, with most of them coming by way of submission too. RIZIN FF will obviously be doing everything in their power to keep Satoshi on their roster seeing as he’s their most successful fighter, but every win also increases the chances that the UFC might come calling for him.
RIZIN 51 Full Results
Roberto Satoshi de Souza defeats Yoshinori Horie via Submission – Rear-naked Choke
Satoshi retains the RIZIN lightweight world championship
Razhabali Shaidullaev defeats Viktor Kolesnik via Knockout – Punches
Shaidullaev retains the RIZIN featherweight world championship
Hiromasa Ougikubo defeats Alibek Gadzhammatov via Decision – Unanimous
Yuki Motoya defeats Makoto ‘Shinryu’ via Decision – Unanimous
Erson Yamamoto defeats Yuki Ito via Decision – Unanimous
Preliminary Card
Aleksandr Soldatkin defeats Marek Samociuk via Decision – Unanimous
Danny Sabatello defeats Shoko Sato via Decision – Split
Genji Umeno defeats Ryusei Ashizawa via Decision – Unanimous
Ryo Takagi defeats Kisa Miyake via Decision – Unanimous
Yusuke Yachi defeats Bilal Haga via Submission – Rear-naked Choke
Hiroaki Suzuki defeats Yuele Huang via Decision – Split
Daichi Tomizawa defeats Joe Hiramoto via Decision – Split
Thiatou Bambilor defeats Kosuke Kindaichi via Decision – Unanimous
Takahiro Okuyama defeats Tetsuya Yamato via Submission – Rear-naked Choke
