Nathan Cleverly retires after losing WBA liht-heavyweight title to Badou Jack in Las Vegas

Fighting on the undercard of Floyd Mayweather’s clash with Conor McGregor, Cefn Fforest’s Cleverly was outclassed by his slick and stylish opponent.

And, after the defeat, Cleverly took to Twitter to announce that he was calling time on his career in the ring.

"Well done to the new champ Badou Jack," he wrote alongside a picture of the pair following the fifth-round stoppage at the T-Mobile Arena.

"Thank you for the opportunity to fight on this event.

"Also, a massive shout out to those that have supported me over the years.

"I've lived it and loved every second of this sport. A few too many miles on the clock. Time to say goodbye.

"Thank you and goodbye boxing."

Cleverly, who made his pro debut in 2005 while a member of Enzo Calzaghe's Newbridge gym, finishes with a record of 30 wins and four losses.

His breakthrough fight came in October 2008, after leaving the Calzaghe stable to be trained by dad Vince, when he outpointed Tony Oakey to win the Commonwealth crown.

British and European straps followed before he became the WBO's interim champion in December 2010.

He was set to face full champion Juergen Braehmer the next year but the German pulled out through injury, leaving Cleverly to take the former's title.

Five defences followed, including one in a grudge match against Tony Bellew, but he was unceremoniously dethroned by Sergey Kovalev in Cardiff in August 2013.

He considered quitting but continued, winning the WBA's inter-continental cruiserweight crown in a short spell at the higher weight, then losing to Bellew and also Andrzej Fonfara for the WBC international light-heavyweight bauble.

In October of 2016 he finally got his chance to fight Braehmer, now the WBA's world champion, and when the veteran German retired through injury during the bout Cleverly got the spoils.

Cleverly, looking to make the first defence of his title last night, put in arguably the worst performance of his career.

A fairly encouraging opening round at the T-Mobile Arena saw the Welshman, 30, make a decent enough start as he squared up against light-heavyweight debutant Jack.

The former WBC super-middleweight king, born in Sweden but now based in Las Vegas as part of Mayweather’s promotional team, did edge the round though.

Cleverly, who was noticeably breathing hard from the outset, finished with a nice right and used his jab well, but a relaxed Jack, 33, found his range quickly.

And from the second round on it was more or less all one-way traffic as Cleverly seemed to sit back and just looked to take evasive action rather than go on the front foot.

Jack alternated between shots to the body and head in the third, finding gaps in Cleverly’s defence with ease.

There was a sign of things to come in round four when two left hooks and an uppercut from the challenger preceded a big left hook left Cleverly in real trouble.

He went back to his corner with blood smeared across his damaged nose and the end looked to be in sight – and it duly arrived in the fifth.

Cleverly had already survived one onslaught on the ropes when Jack piled even more pressure on and a stiff right was followed by more shots that forced referee Tony Weeks to step in.

There was no doubt about the official's decision to end the contest.