I watched the video closely, more than once. She clearly did something, threw/sprayed something.
It doesn’t matter. The sucker punch was STILL police brutality. It was an excessive use of force in apprehending and arresting the woman.
Thug behavior towards citizens is unacceptable, most especially in response to immature, petty behavior. Pretty soon they start shooting dogs and busting doors down without warning... oh wait, never mind.
This “officer” should lose his job and his pension.