Miguel Cotto ended his 16-year long career with a unanimous points-decision defeat against Sadam Ali in New York.
The 37-year-old had announced before the fight that his defence of his WBO light-middleweight title would be the last time he would enter the ring.
Cotto had won four titles in four different weight categories, but struggled against the quick hands of 29-year-old Ali.
Judges scored the fight 115-113, 115-113, 116-112 in favour of 29-year-old Ali, who is from New York.
Following his defeat at MSG, the Puerto Rican fighter said that he was happy with his performance and he was looking forward to going home to be with his family.
"I am good, and I want to be happy in my home with my family,
"I'm feeling good with the performance,
"Something happened to my left biceps but I don't want to make excuses, Sadam won the fight.
"I am proud to call MSG my second home. I had the opportunity to provide the best for my family because of the sport."
Miguel Cotto’s fight record ends on 41 wins and six defeats.
The 37-year-old suffered injury to his left bicep during the seventh round at Madison Square Garden, and there after struggled to have any further influence on the bout.
Tony Bellew tweeted his support for the veteran boxer, however, whilst stating that young fighters could still learn a lot from him.
“Gutted for Miguel Cotto! This is a young man’s game and also a very unforgiving sport.. He is a true legend in my eyes, An Icon for the younger fighters to study and watch, Technically brilliant.. I hope he enjoys his well-earned retirement 👊 #MiguelCotto #Legend”
The love for Cotto did not stop there.
Sadam Ali, the new WBA title holder, had this to say about his illustrious opponent.
"I want to thank team Cotto. They could have taken an easier fight if they wanted too. I had him hurt here or there in the first couple of rounds. I knew I had to do something, or he would have dug in."