SB 10.66.21

iti kṣiptvā śitair bāṇair
 virathī-kṛtya pauṇḍrakam
śiro ’vṛścad rathāṅgena
 vajreṇendro yathā gireḥ
Word for word: 
iti — with these words; kṣiptvā — deriding; śitaiḥ — sharp; bāṇaiḥ — with His arrows; virathī — chariotless; kṛtya — making; pauṇḍrakam — Pauṇḍraka; śiraḥ — his head; avṛścat — He cut off; ratha-aṅgena — with His Sudarśana disc; vajreṇa — with his thunderbolt weapon; indraḥ — Lord Indra; yathā — as; gireḥ — of a mountain.
Translation: 
Having thus derided Pauṇḍraka, Lord Kṛṣṇa destroyed his chariot with His sharp arrows. The Lord then cut off his head with the Sudarśana disc, just as Lord Indra lops off a mountain peak with his thunderbolt weapon.