The boxing world was in mourning Friday following the death of Puerto Rican fighter Prichard Colón at the age of 33, 11 years after he sustained brain damage in the only defeat of his professional career.

Colón’s death was confirmed in statements by the World Boxing Council and the World Boxing Organization late Thursday.

In October 2015, Colón suffered a brain bleed in a light-middleweight fight against Terrel Williams in the Washington, D.C., suburb of Fairfax, Virginia.

Colón underwent surgery to relieve pressure on his brain and the WBC said he sustained “irreversible neurological damage” because of what the governing body described as “severe, illegal blows to the back of the head.”

He never fought again and was later pictured in a wheelchair. The WBC named him an honorary world champion.

“The ‘Champion of the Heart’ became a global symbol of resilience, faith, and dignity,” said the WBC, which added that the incident involving Colón inspired the governing body to reinforce its safety regulations and implement stricter medical protocols.

The WBC praised his family for its support in “one of the most moving and outstandingly brave battles for life the world has ever witnessed.”

The WBO described Colón as “a warrior until the very end” and said his “courage, strength and fighting spirit transcended the ring.”

“His greatest fight became a testament to resilience and the unwavering love of his family,” the WBO added.

Before the fight against Williams, Colón collected 16 straight wins, including 13 knockouts.

He lost by disqualification against Williams because his cornermen removed his gloves after the 10th round, believing the contest to be over.