According to reports from Argentina and Spain, Lionel Messi was punched by a teenager as he signed autographs outside a restaurant in his hometown of Rosario. Messi was eating with two friends and no security. After they finished, he signed autographs and took pictures outside with the mob of fans that had spotted him, at which point a kid shouted, "I'm a Central supporter, you're from Newell's" and punched him. He then ran away, chased by a pack of Messi fans (which I imagine was quite funny looking) as Messi himself just left without reacting.
Messi began his youth career with Newell's Old Boys, Rosario Central's fiercest local rivals, which explains why the kid felt the need to declare his support (I guess he didn't want anyone thinking he was a Real Madrid fan).
Given all the witnesses to the incident, I'm sure there will be more on this to come.
UPDATE: Messi told Ole, "I felt nothing and I only learned of it after the hype. Nothing happened." So was he actually hit or is he just impervious to mere mortals' attempts to hurt him?
UPDATE II: OK, so he might not have felt the punch, but he had to feel the lady in the picture squeezing his cheeks. Pretty sure that counts as assault too.
UPDATE III: Here's an eyewitness account from the AP:
"There was a crush of people waiting outside," Pablo Moyano, who was working in the restaurant, told Argentine TV. "There were kids, reporters, photographers waiting … and one of the kids tried to punch him. I don't know if he pulled it off. He went running afterward."
Witnesses said the suspect was dressed in the uniform of a school a few streets away.
Now we are left to wonder how Cristiano Ronaldo got a hold of a local school uniform.
UPDATE IV: Here's video of the incident...
Unfortunately, it looks like the kid wasn't really chased. It also appears he is at least four times larger than Messi, which makes it that much worse.