I don't really think that driving well, in a single GP gives you the right to say that "you are worthy of the championship".
At the end of the day Hamilton has been far more consistent and in the early part of the season seemed intent on breaking the overtaking record. Hamilton has shown that in an inferior car he can beat other drivers.
The driver of the season, so far, for me, is definitely Hamilton.
Button has done extremely well, as he is not getting obliterated by his team-leader. But Hamilton edges it for me.
I've been very critical of Alonso this year, namely because he is widely regarded as the daddy of F1, yet, he has been making silly little errors (example: the Spa debacle) which are costing him points. All these lost points are adding up. He is in 3rd place and I am confident he will finish up as the top point scorer in the 2nd half of the season. If he can do this, then maybe he may be worthy for the championship, but at this point, based on what we have seen this year, he is definitely not worthy of the championship or his tag of being the best driver in F1.