Harry thought he was ready, but he wasn't expecting Remus to move that quickly, or attack him without pause. It was a good thing Harry had great reflexes because while the jab to his stomach landed and knocked the breath out of him, he was able to recover quickly enough to dodge away from the low hook which grazed his ribs with fiery pain. The upper cut came in and he sidestepped at the last second, aiming a hard punch towards Remus' side while it was unprotected.