I just came across an interesting blog on the bleacher report comparing the greatness of Roger Federer and Tiger Woods.

Here in Italy, the Gazzetta dello Sport newspaper has been running a series called "Impossible duels" where the likes of Michael Phelps and Usain Bolt have gone up against each other in a bizarre statistical battle.

But if there is even a debate about whether we can say Federer is the greatest player in tennis, how can we start to compare across sports?

We can talk about desire, mental toughness etc but the sports are so radically different.

Despite my doubts, here goes. Who was/is the greatest sports personality ever?

CAPTION: Can you name all the sporting figures in this photo?

It has been quite a day in the world of sport, especially for tired sports journalists.

Rafael Nadal lost to Robin Soderling in the fourth round at the French Open. Yes you read that right. The four-time champion's 31-match winning streak at Roland Garros is over.

Less of a surprise was Carlo Ancelotti saying he was leaving as AC Milan soccer coach, although he refused to confirm he is heading for Chelsea.

To cap a frenetic day, Russia's Denis Menchov won the Giro d'Italia despite falling over only seconds from the line.

I forgot why I love sport so much....