Well, he played pretty well at AO this year and then turned into some mug.
Brian Baker - Steve Johnson - Lleyton Hewitt - Robby Ginepri - Carlos Berlocq - Tommy Haas - Ivo Karlovic - Richard Gasquet - Kevin Anderson - David Ferrer - Michael Russell - Fabio Fognini - Michael Llodra - Oliver Rochus - Dustin Brown - Somdev Devvarman
You're right, Bellucci is a good player especially on clay.
But it's the way he lost it : Gonzo was leading 6-3, 4-2 (didn't face any break points) and was the two defending champion...This defeat was already worrying.
Most likely the earthquake and its effects are still on his mind.
Otherwise, he could be another player falling victim to his age...obviously not everyone falls off the map at 29-30 years old, but when you consider how long he has been near the top of the game, it is inevitable that his level would drop at some stage.