Daiki Yonekura vs Baby Shark / Lachlan Giles vs Marcelo Garcia

While ONE Championship is best known for its explosive MMA, Muay Thai, and kickboxing matchups, the December 6 event at Lumpinee Stadium in Bangkok will also feature two historic grappling bouts that no jiu-jitsu fan should miss.

In the co-main event, Japan’s Daiki Yonekura will challenge Diogo “Baby Shark” Reis, the reigning ONE Grappling Flyweight Champion and two-time ADCC World Champion.

And in a dream matchup for grappling fans worldwide, the legendary Marcelo Garcia, returning from cancer treatment, will face Australia’s Lachlan Giles, who makes his own comeback after years away from competition.

Below, we break down both matches and highlight what to watch for.

Event Overview

• Date: December 6, 2025 (from 11:00 AM JST)
• Venue: Lumpinee Stadium, Bangkok
• Streaming: Available on U-NEXT in Japan

Daiki Yonekura vs Diogo “Baby Shark” Reis

(Co-Main Event – ONE Grappling Flyweight Title)

Japan’s leading grappler, Daiki Yonekura, known for his international performances in AIGA and other elite tournaments, will face the reigning flyweight king, Diogo Reis, one of the most accomplished lightweights in grappling history.

Reis, nicknamed “Baby Shark,” is a two-time ADCC Champion (2022 & 2024) and widely regarded as the pound-for-pound best in his division.
(For a complete profile on Baby Shark’s background and style, see our previous feature and podcast episode.)

Key Storyline 1: Can Yonekura Create His Game from the Bottom?

The match will likely open with Yonekura pulling guard and Baby Shark applying pressure from the top.

In his last bout — against Shoya Ishiguro — Baby Shark relentlessly forced his way through passes, maintaining heavy top control that left Ishiguro unable to build any meaningful offence.

For Yonekura to win, he’ll need to establish his guard, control the distance, and initiate attacks instead of just defending.
Under ONE’s submission-oriented ruleset, successfully setting up submission threats can heavily influence the judges’ perception — even if the finish doesn’t come.

If Yonekura can consistently create attacking positions from the bottom, the momentum could swing his way.

Key Storyline 2: Baby Shark’s Conditioning and Weight Cut

In his last ONE appearance, Baby Shark missed weight, leading to his fight with Ishiguro being changed to a catchweight. This time, as a championship match, there’s no room for error.

Although he used to compete comfortably at 62 kg or below earlier in his career, his recent bouts have been at 64–70 kg. At age 23, his body is still maturing, and the weight cut may not be as easy as before.

Whether he can make weight cleanly — and how well he performs physically after doing so — will be key factors on fight night.

Marcelo Garcia vs Lachlan Giles

The second grappling matchup is a legend vs tactician showdown:
Marcelo Garcia, a living icon of Brazilian Jiu-Jitsu, vs Lachlan Giles, one of the sport’s most respected modern technicians.

Marcelo Garcia – The Return of a Legend

Marcelo Garcia is one of the greatest grapplers in history.
He won the ADCC World Championship (77 kg) in 2003, 2005, 2007, and 2011, and multiple IBJJF World titles (2004, 2006, 2009–2011).

He revolutionized the art with his signature butterfly guard, X-guard, and high-elbow guillotine (the “Marcelotine”) — techniques that remain staples of modern jiu-jitsu.

In 2023, he publicly revealed his battle with cancer and stepped away from the sport. But in February 2025, he made a triumphant comeback, defeating Masakazu Imanari in his return match under ONE Championship.

Lachlan Giles – The Heel Hook Innovator

Marcelo’s opponent, Lachlan Giles, is best known for his bronze medal in the ADCC 2019 Absolute Division, where he submitted multiple heavier opponents with heel hooks from innovative K-guard and backside 50/50 entries.

After the 2022 ADCC Worlds, Giles largely stepped away from competition — focusing on teaching and developing new systems — but announced his return specifically for this match against his hero, Marcelo Garcia.

Key Storyline: Can Marcelo Neutralize Lachlan’s Leg Attacks?

Although both men are in their late 30s to early 40s (Marcelo 43, Lachlan 39), they represent different eras.
Marcelo dominated in the 2000s–early 2010s, before the leg lock revolution took over. Lachlan, meanwhile, rose to prominence in the late 2010s — after the Danaher Death Squad’s systematic approach to lower-body attacks reshaped the sport.

In his comeback fight against Imanari, Marcelo successfully avoided leg entanglements through wrestling pressure and top control, but Giles is a true specialist — and a closer physical match in size.

If the fight transitions into leg entanglement exchanges, the question becomes:
Can Marcelo adapt to the modern leg lock game?
Or will Lachlan’s timing and innovation overwhelm the legend’s classic pressure style?

Either way, this matchup bridges two generations of jiu-jitsu — and promises a fascinating technical showcase.

📺 How to Watch

Both grappling matches — Yonekura vs Reis and Garcia vs Giles — will be broadcast live as part of ONE Championship: December 6 on U-NEXT in Japan.