Jannis Loose Battles WBC & ISKA Champion Kevin Guillen Pereira — Now Fighting in ONE Championship

On January 13, 2025, Jannis Loose stepped into the ring at Max Muay Thai against Kevin Guillen Pereira — a fighter with credentials that few on the Thai circuit can match.

Pereira is a WBC Muay Thai champion, an ISKA world champion, and has since gone on to sign with ONE Championship — the world’s largest martial arts organization. This was not just another fight. This was a test against elite-level, world-title-caliber competition.

From the opening bell, Pereira’s size advantage was evident. Standing taller and with a longer reach, the champion utilized his physical gifts to control the distance. He landed the cleaner shots from the outside, dictating the pace and keeping Jannis at the end of his strikes.

But Jannis is not a fighter who backs down. Round after round, he walked forward — constantly pressuring Pereira and forcing the fight into close quarters. The game plan was clear: smother the champion, take away his range, and make it a dogfight.

Pereira, however, proved why he’s a world champion. His unorthodox style made him a difficult target to pin down. He avoided going punch-for-punch with Jannis, using movement and angles to slip away from the pressure and reset to his preferred distance.

After three hard rounds, the judges awarded Pereira a unanimous decision victory. A fair result against a fighter who has since ascended to the global stage of ONE Championship.

For Jannis, it was a fight that showed he belongs in the conversation with elite competition. Taking a WBC and ISKA champion — now a ONE Championship athlete — to a decision is nothing to dismiss.