SB 10.78.12

tasya cāpatataḥ kṛṣṇaś
 cakreṇa kṣura-neminā
śiro jahāra rājendra
 sa-kirīṭaṁ sa-kuṇḍalam
Synonyms: 
tasya — of him; ca — and; āpatataḥ — who was attacking; kṛṣṇaḥ — Lord Kṛṣṇa; cakreṇa — with His Sudarśana disc; kṣura — like a razor; neminā — whose edge; śiraḥ — the head; jahāra — removed; rāja-indra — O best of kings; sa — with; kirīṭam — helmet; sa — with; kuṇḍalam — earrings.
Translation: 
O best of kings, as Vidūratha fell upon Him, Lord Kṛṣṇa used His razor-edged Sudarśana disc to remove his head, complete with its helmet and earrings.