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A month after dropping a unanimous decision to 21-year-old junior middleweight titlist Saul "Canelo" Alvarez, "Sugar" Shane Mosley announced his retirement on Monday.

"Good morning everybody. Just want to thank you for showing me so much love," Mosley tweeted. "Had a great career and loved every moment of it, win, lose or draw."

During Mosley's illustrious 19-year career, the 40-year-old won five world titles in three different weight classes, including a memorable welterweight championship victory over Oscar De La Hoya in 2000.

"I'm going into the promotional world, I'm training my son (21-year-old amateur Shane Mosley Jr.). It was a helluva career. I'm happy for all the great memories and all the great fighters that I fought. Now it's time give back. I'm ready to train my son full-time now," Mosley told ESPN.com.

Mosley, who was never knocked out in his career, posted a 46-8-1 mark, but was 0-3-1 over his last four fights. These included bouts against Floyd Mayweather Jr. and Manny Pacquiao.