Iris was impressed when he blocked her uppercut. As he pushed her arm away she spread her legs farther apart, widening her base of support. She leaned back just enough for his fist to painfully nick her chin. As she leaned back, she started feeling unstabe so with her right hand she grabbed his arm and with her left, aimed a jab at him. 

It was just below his collarbone it was going to hit because of her hight and wavering balance.