Klitschko proved his heavy mettle

The pantheon of boxing's all-time greatest heavyweight champions is very exclusive - Muhammad Ali, Joe Louis, Jack Johnson, George Foreman - so it's no disgrace to be firmly ensconced in the second tier.

That's right where Vitali Klitschko belongs: just south of Sonny Liston, Larry Holmes and Lennox Lewis, but ahead of Jack Dempsey, Rocky Marciano, Joe Frazier and Mike Tyson.

Klitschko announced this week he is giving up the WBC title he's owned since 2008 and walking away from boxing to pursue a bid for the presidency of Ukraine in 2015. While not calling it a formal retirement, the 42-year-old gave every indication we've seen the last of him in the ring. If that indeed is the case, he's stepping out on top.