In October 2021, Fuentes entered the ring after more than a three-year hiatus to face undefeated puncher David Cuellar in Cancun. Fuentes suffered a heavy knockout loss in the sixth round. Fuentes had previously lost twice in a row to Daigo Higi and Roman Gonzalez ahead of schedule.
After his last defeat, Fuentes was carried out of the ring on a stretcher and quickly taken to a hospital in Quintana Roo. He was found to have a large blood clot in his brain, and he underwent emergency surgery. The operation saved Fuentes' life, but he could not fully recover, and he had to deal with numerous health complications that affected his quality of life.
"Moises Fuentes, rest in peace. A warrior who fought to his last breath. Our condolences to his family and friends and our gratitude to his wife for her dedication and indescribable love during this difficult year of suffering. May he rest in peace,” wrote Suleiman in one of the social networks.
Fuentes fought eight fights for the world title. In 2011, he won the World Boxing Organization's strawweight title by defeating Raul Garcia. He also scored a stoppage victory over Puerto Rico legend Ivan Calderon in defense of his title. Fuentes won the interim WBO flyweight title in 2013.
In his 33 professional fights, Fuentes won 25 victories, 14 of them by knockout. He had one draw and seven losses.