Calzaghe beat WBA and WBC super-middleweight king Mikkel Kessler in 2007
Joe Calzaghe has been hailed as "British boxing's greatest ever fighter" by his former stable-mate and life-long friend Gary Lockett.
Undefeated world super-middleweight and light-heavyweight champion Joe Calzaghe announced his retirement on Thursday.
The 36-year-old Welshman, reigned as a world champion for more than 11 years with a glittering record of 46 wins from 46 fights.
"He has the skill, illusiveness and heart of a champion," said Lockett.
Former WBU middleweight champion Lockett, who quit boxing last year, trained at the same gym in Newbridge as Calzaghe and also sparred with him.
"I'm happy for Joe that he's decided to call a halt to his career at exactly the right time," Lockett added.
"It is one of disappointment for me too because even though he is a friend of mine, I'm also one of his biggest fans.
"I've thoroughly enjoyed watching him over the years and even commentated on his last fight in New York."
Former Commonwealth light heavyweight champion Nicky Piper also hailed Calzaghe's achievements.
I sensed he had lost ambition within the sport and lost the love for it
"If you judge him on paper and achievements, you have to put him at the very top of course," said the Welshman.
"He has certainly put Welsh boxing on the map. The last 20 years have been good for Welsh boxing."
And Piper says he understands Calzaghe's decision to quit.
"It's more difficult for Joe because he's still the world champion, still undefeated, and still has the possibility of earning $10-15m a fight which is a massive temptation for any sportsman," he said.
"I spoke to him about six months ago and I sensed he had lost ambition within the sport and lost the love for it.
"When that starts to happen in boxing, you really have to start considering retirement and he's done it and fair play to him."
Piper added: "There's a lot of work that goes into it (boxing). It's not just what you see on the television.
"Getting up and doing the running every morning up the hills then sparring in the ring with young guys every night gets hard.
"But there are some brilliant boxers Enzo Maccarinelli, Bradley Price and Gavin Rees are still going through that gym.
"So Welsh boxing is in a very good position at the moment."