The turning point in the battle had come with Quinn's use of the blood shadow, creating minuscule shields that could be moved at a great speed. It was enough for him to turn the tide.
Mundus knew it was the end, Asura knew it was the end, and so did Quinn. Yet even then, Asura didn't stop trying. He continued to throw out his fists, each one of them deadly, with the way Quinn's health was now, a single hit meant it was the end of the fight.
Maybe Asura was unaware of this, if he had known, perhaps it would have made a difference, but either way Quinn wasn't letting up. He continued to block all of Asura's hits, now having more of the floating circles, and his own two arms compared to Asura and had done the same again.