I win, but i lose?

I was wondering how you all might interpret this scenario. My character was engaged in combat with a dangerous foe. Due to lucky rolls, he maintained initiative without enduring a harm. After inflicting 6 harm on the progress chart I decided to attempt to end the fight. I rolled a 9 and a 10. That’s a fail. I endured no harm, inflicted 6 and lost the fight. What happened? Did I trip on a rock and crack my skull open? Or, do I need to enter the fray again? What happens if I inflict 10 harm?

Just curious how you would interpret these situations.