seconding Thomas Percy - if your son is being realistic about his abilities, that is an amazing milestone and completely healthy. it would concern me if he was actually very strong in the activity and was curtailing his own potential due to one poor showing. (i do have a bit of a bee in my bonnet about perfectionism because that's been DD8's biggest issue since she was very young!)
i'd keep an eye out for more data points - just file this in the back of your brain for a bit and see if it's a one-off, or part of a larger trend...
DG
