Madhav saying Yudhishtir tat "Guru Dhron will scarifice his weapon/ its easy to defeat him (Sorry doesnt understand clearly") if Ashwathama gets killed,Mean while they showed Ashwathama in war field... Yudhishtir and Guru Dhron came face to face in war field and Yudhishtir says to Guru Dhron tat "Im saying the Truth Guru dev, i just saw Ashwathama gets killed" Dron left his weapon and cried shouting Ahwathama, Right then they showed Dhrishtadyumna cuts his neck, when Guru Dron is on his knees and crying for Ashwathama.
Will post the Link, after getting it!!