...that the ball touched the ground.
I don't think the question being asked as far as whether it was a catch or not was if the ball touched the ground. The question is did he catch it and then lose it as he went down, or did he not ever have it securely in his possession enough to qualify it as a catch.
But it was pretty clear from one of the replays I saw on TV that that ball did touch the ground as he went down.