Interesting. Seems very similar to what we saw with our DYS DS9 at that age. Frankly, that first year, DH and didn't know whether to chuckle or hide. It was bizarre to us, because DS was VERY coordinated when we played with him in our yard, but it just didn't translate onto the field/court.
Like your DS, ours also did much better at practice than at actual games for both basketball and soccer at that age. We have seen, in MANY situations, including the classroom in K, that DS has trouble tuning out new stimuli. He used to spell words in the air with his fingers as he was running down the court -- I actually heard people once asking quietly if DS was impaired *lol*. But that seemed to be his way of coping with what was going on around him. FWIW, it's MUCH better now, although it's still somewhat difficult for him to adjust to new high-stimulation surroundings.
Not sure if it's the same thing for yours, but food for thought.
