Diogo Reis vs. Bebeto: the belt Musumeci lost on the scale
The December 18 match goes back to Denver, where Bebeto made weight, Musumeci lost the title and the belt went vacant
Diogo “Baby Shark” Reis will make the first defense of his ONE Championship flyweight submission grappling title against Carlos “Bebeto” Oliveira. ONE announced the match on Tuesday. It takes place at ONE Fight Night 50 on December 18 at Lumpinee Stadium in Bangkok, with the event set for 9 p.m. ET and streaming on Prime Video in the U.S. and Canada.
The story behind this match started two years ago. Bebeto came very close to this same belt in 2024, and the VF Comunica archive shows how that chance slipped away.
The belt went vacant after Denver
In September 2024, Kade Ruotolo got hurt and pulled out of his match with Mikey Musumeci at ONE 168 in Denver. Bebeto took the spot less than 48 hours before the event, in a match for Musumeci’s flyweight title.
Bebeto made weight and passed his hydration test. Musumeci failed and lost the belt on the scale.
That same day, ONE’s vice president of grappling, Leo Vieira, gave VF Comunica an exclusive account of how the match came together. “The short version is that after Kade Ruotolo’s injury was confirmed, Mikey Musumeci was offered a new opponent as a replacement. In response, Mikey made some demands, and the most important was that the match would no longer be at 170 pounds, but in his own division, as a defense of his flyweight title at 135 pounds,” he said.
Vieira also explained how the talks ended. “During the weigh-in, Mikey repeatedly failed his hydration tests and asked for the match with Bebeto to happen at open weight. During negotiations with Bebeto and his team, Mikey told everyone he was withdrawing from the event and would not compete, which made any deal impossible.”
Musumeci later revealed he had been hospitalized, and he left ONE a few weeks later. Bebeto left Denver without competing. The belt stayed vacant until December 2025, when Diogo beat Daiki Yonekura by unanimous decision.
What Diogo said about Denver and the UFC
In October 2025, a few weeks before he won the title, Diogo sat down for an exclusive interview on the VF Comunica YouTube channel, in Portuguese. He said a knee injury had delayed his match with Musumeci, then summed up what came next. “Then he was going to fight Bebeto, he didn’t make weight there, right? Then he left the event,” Diogo said.
That is how the title reached him. “Since I already had a signed contract, I made my debut, right? And now they said, ‘Let’s do a title fight in this division.’ That’s what I’m going to do now.”
Diogo also confirmed that the UFC had reached out. “Yes, yes, they already did, right?” he said. He chose to stay with ONE. “I said, ‘Then I’ll stay here and keep my word.'”
The 135-pound limit is back at the center
ONE’s flyweight limit is 135 pounds. In his promotional debut in March 2025, Diogo missed that mark, and his match with Shoya Ishiguro took place at 139.5 pounds. He submitted Ishiguro and fought for the title in the division nine months later.
In the interview, Diogo described the cut as natural for him. “When I make light featherweight at the Worlds, I’m close to that weight, you know?” he said. Talking about possible opponents for Musumeci, though, he admitted how demanding it is. “Because it’s hard to make 61 kilos, right?”
Diogo’s last ONE match came one division up, at bantamweight, with a win over Yuki Takahashi in May. In October, he won three matches at featherweight at the Rio Spring Open No-Gi, two by submission. Bebeto is a gi world champion at roosterweight, a 127-pound division, and competed at light featherweight at this year’s Pan No-Gi.
Guard passer against guard player
They have met before. In the under-62-kilo final of the 2021 AJP Grand Slam in Miami, Diogo won 1-0.
Five years later, the rules are very different. ONE matches run one 10-minute round. Without a submission, judges look first at real submission attempts, and pulling guard has to be an attacking move.
The IBJJF describes Bebeto as a strong guard player who is dangerous with submissions. Diogo talked about this kind of matchup in 2025 while breaking down a possible fight with Musumeci. “It would be that fight of guard passer against guard player, right?” he said.
He also explained what changed in his game. “Especially in this type of ruleset, where there are no points. So I know what counts is the submission. In that time, I managed to improve a lot of my attacks during my guard passes, you know?”
Leg locks could matter here. Bebeto submitted Mathew Isaacs with a heel hook at the Pan No-Gi in October, but lost to Jalen Fonacier by the same move at UFC BJJ in 19 seconds. Diogo clinched his second ADCC title by submitting Diego Pato after escaping his rival’s leg attacks.
How each one gets to Bangkok
Diogo is 3-0 in ONE and was named the promotion’s Submission Grappler of the Year for 2025. In July, he beat Rerisson Gabriel at Connect Heroes, the man who had beaten him in the 2025 Pan final.
Bebeto reached three roosterweight finals at the Worlds in four years and won gold in 2024, submitting Zayed Alkatheeri. That same year he also won the Master Worlds. In 2026, he took silver at the Pan and reached the Pan No-Gi semifinals.
In 2022, before the Worlds, he told VF Comunica how he approaches every tournament. “No matter the results, I keep the same focus in every competition. Champion’s mind.”
Will Diogo repeat the Miami result, or will Bebeto take the belt that got away in Denver? Who wins this one?
