Bacha's brown belt campaign stands as one of the most accomplished pre-black belt runs in the ultra-heavyweight division in recent memory. The pinnacle of that period arrived at the 2021 IBJJF World Championship, where he swept through the Pesadíssimo bracket (+100.50 kg / +222.0 lbs) undefeated to claim gold. His performance proved instrumental in Checkmat securing their first-ever IBJJF Team World Title — a historic milestone for the organization. That same year, Bacha also captured gold at the IBJJF Pan Championship and the AJP Abu Dhabi World Pro at brown belt, demonstrating a rare capacity to perform at the highest level across multiple major competitive circuits simultaneously.
His colored belt résumé — spanning IBJJF, AJP, and domestic American events — established him as the premier ultra-heavyweight competitor outside the black belt division. On December 13, 2021, Ricardo Vieira and Leonardo Vieira awarded Guilherme Bacha his black belt, bringing to a close one of the most decorated colored belt careers in the super-heavyweight category.