God and the Applicability of Mathematics

Dr. Craig,
In your recent debate with Dr. Rosenberg, you bring to the table two new arguments (at least that I've never seen you propose before). I am enamored with the argument against naturalism based on intentionality. My question regards the argument against naturalism based on the applicability of mathematics.
Isn't it the case that mathematics could, and in my opinion does seem to be, just a useful fiction as you mentioned in your debate? You say something along the lines of "this wouldn't explain how nature seems to be written in the language of mathematics". Isn't it also the case that if mathematical concepts are useful fictions, then they would describe (accurately if well thought out) the universe as apprehended by our perceptions? Shouldn't we expect that our useful fictions would be useful precisely because they accurately describe our observations?
I have thought that perhaps I am missing the point of the argument though. Perhaps it is the case that you aren't saying God must exist because our useful fictions, particularly those of mathematics describing reality, would just be happy coincidence. Indeed, what kind of coincidence would it be that our tools were designed for the purpose they serve? Perhaps you are making the point that without God the universe wouldn't necessarily exhibit these extremely logical properties.
Maybe I'm just completely wrong headed on this. Could you please set me straight?
Keep up the great work for God,
Brad
Read Dr. Craig's answer HERE