For boxing manager Pat Lynch, this is worse than any loss in the ring.
His friend and fighter, Arturo "Thunder" Gatti, was found dead in a Brazilian hotel room under suspicious circumstances. Gatti is a legend among boxing fans for his trilogy of thrilling and brutal fights with "Irish" Micky Ward, and fought to the limit of his endurace in many epic bouts.
The Italian-born Canadian captured world titles at Super Featherweight and Junior Welterweight during his 16-year-professional career and also fought and lost to legends Oscar De La Hoya and Floyd Mayweather Jr. in big-money matches.
"It tears me apart," Lynch says. "It's much more than a manager-fighter relationship. Arturo was family to me. I married an Italian girl; she cooked for Arturo," Lynch said. "And he's the godfather of my eldest daughter."
Lynch treated Gatti like a son, and worried himself sick when Gatti was knocked around the ring."I prayed for him before every fight," he said.
"I've been very lucky to have survived in a world as tough as boxing," Lynch said. "It's all because of the trust and loyalty that Arturo gave me."
Gatti's 2002 and 2003 bouts with Ward will always be the best-remembered by fans, and two of them won the "Fight of the Year" award given by Ring magazine.
The first two fights laster more than 10 rounds, with Gatti losing the first and gaining revenge in a classic second bout.
The third and deciding fight took place in June 2003 and Gatti broke his right hand in the fourth round. Incredibly, he fought on, and despite being floored in the sixth, dominated the rest of the fight to win.
But the storied wins over Ward proved to be the high point of Gatti's career.
He made two successful defenses of the title against easy opponents until running into Mayweather in 2005. It proved a big fight too many as he was slowed by body shots. The fight was stopped in the sixth round.
Moving up to welterweight, Gatti won a warmup fight before losing to Carlos Baldomir in a world title bout.
His comeback fight, with old rival Ward now his trainer, also ended in defeat to Alfonso Gomez in July 2007. He then announced his retirement.
It ended a 49-fight career with 31 knockouts and nine defeats. His first world title had come with victory over Tracey Patterson, the adopted son of heavyweight great Floyd Patterson, to claim the IBF Super Featherweight crown.
As his fame spread, and with countless nominations for Ring's Fight of the Year, Gatti gained a large and devoted following among boxing fans.
But his life outside the ring proved contentious, and in March this year Gatti was charged with assaulting his then-girlfriend Amanda Rodriguez and spent two nights in jail after failing to turn up for a court appearance.
Gatti later married Rodriguez and they have a one-year-old young son. She has been arrested in connection with his death.