Challenge him to a duel

While your fellow riders were still hesitating you trotted alone towards the knight.

"Greetings Sir, I am Garrick Heselrig. You have earned my respect for your bravery."

The knight looked you up and down. "My name is Sir Patrick Graham. We are fighting for our homeland and will die in duty if needed. Seeing the look in your eyes I know that you want to challenge me in the hope to gain fame and glory."

"Yes, Sir. I want to challenge you to a duel. I hope you will grant me this wish."

"We are fighting a war but seeing your courrage I have to respond in kind. I accept your challenge."

He removed his helmet and passed it to one of his retainers and only now could you see that he must be a man already in his sixties. He ordered his men to step back and confront you with a short sword and kite shield. He was a skilled fighter and it was hard exchanging blows with him at first. However he was also an old man fighting against a youngster in his prime. After a while his moves became more slowly due to tiredness. You take an opportunity and finally disarmed him with a barrage of attacks.