Valmiki Ramayana Yuddha Kanda Sarga 101 Shloka 14

महाद्युतिः endowed with extraordinary splendour, महावेगैः at high speed, तैःसायकैः those shafts, तस्य his, रावणस्य Ravana's, मनुष्यशीर्षम् device of human head, ध्वजम् flag post, नैकधा one, चिच्छेद shattered

Lakshmana, who was endowed with extraordinary splendour, for his part, with his shafts which had great force, shattered the device of man's head on the flag post of Ravana.