World light heavyweight champion Andre Ward announced his retirement from boxing on Thursday, saying his weary body could no longer put up with the physical demands of the sport.
Ward, 33, is the reigning WBA, IBF and WBO champion and is widely regarded as one of the best pound-for-pound boxers in the world.
He leaves the sport after recording back-to-back wins over Russian brawler Sergey Kovalev, hanging up his gloves with a perfect 32-0 record.
"I want to be clear - I am leaving because my body can no longer put up with the rigors of the sport and therefore my desire to fight is no longer there," Ward said in a statement on his website.
"If I cannot give my family, my team, and the fans everything that I have, then I should no longer be fighting," he added under the statement, titled "Mission Accomplished."
Ward added that he was leaving the sport at the pinnacle as he had intended.
"As I walk away from the sport of boxing today, I leave at the top of your glorious mountain, which was always my vision and my dream. I did it. We did it," he said.
In a separate interview with ESPN's First Take program, Ward said the intensive training camps for title fights had taken a steady toll on his body.
"People see what I do fight night. They see under the lights, but they don't see the toil, they don't see the grind, they don't see just the pain, the physical pain that you go through, not just in the fights, but to prepare and to get ready for those battles," he said.
"I felt the physicality of the sport, not just in the ring stuff, but the training and the preparation, start to take its toll on me for the last two or three years, and I bit down and continued to push through, and at this point, it's time, and I know it's time," he added.
Ward, a gold medallist at the 2004 Olympics in Athens, had been a controversial victor over Kovalev last November, winning the Russian's three 175-pound belts with a unanimous decision.
However he silenced those doubters with a decisive eighth-round knockout in the rematch in June.