By Igor Lazorin, tass

In the opinion of former undisputed heavyweight champion Lennox Lewis, 39-year-old Alexander Povetkin should call it a day and retire from boxing.

Last week, Povetkin was knocked out in seven rounds by the World Boxing Association (WBA), World Boxing Organization (WBO), International Boxing Organization (IBO) and International Boxing Federation (IBF) heavyweight champion, Anthony Joshua.

At this stage of his career, securing another world title fight will be extremely tough.

Povetkin holds a record of 34 wins, 24 of which he won by knockout, and only two defeats. The Russian fighter is also a 2004 Olympic gold medal winner, a former world champion and two-time European champion.

Against Joshua, Povetkin started off quickly and soon found himself out of steam, says Lewis.

“Povetkin started the fight too active, by the middle of the fight he just ran out of gas,” Lewis said.

“Although, of course, he made a couple of good attacks. But this was not enough, because Joshua calmly stepped in and did his job. Anthony can be beaten by someone who is well prepared physically, not for half the fight, but for twelve rounds.

"As for Povetkin, I think he needs to finish his career, he would become an excellent ambassador for sports and boxing."

Another former world champion and Hall of Famer, Kostya Tszyu, felt Povetkin had only one game plan in place - with no Plan B.

 "This fight proved once again that youth will win win in most situations," Tszyu said.

"There were many moments in the fight when Povetkin demonstrated a good level and coped with his work perfectly. Alexander had a certain plan prepared, but he only had one. He did not have a backup [plan] for the fight. Povetkin got off to a good start, went through some good moments, but Joshua managed to adapt, and Alexander could not reorganize."