Does the ball go to the defense, or the defense?? Need to settle a bet.

[johnyd]

GJrHi game, I was lead and handed the ball off to an inbouder, stepped away and started a count. She slaps the ball and yells "GO", knocking the ball out of her own hand, bounces off the top of her foot and lands in bounds, where a defensive player recovers.
I let play go on, but my partner blew it dead, thinking that we had a bad hand off and the girl fumbled.
We gather and I explained what happened. He says "it cannot bounce out of bounds before it bounces in bounds, it is the defense ball." I say, it did not bounce out of bounds, it bounced off her foot and directly in bounds.
Still defenses ball. But Who was right?