876 aṅguṣṭhākrāntakaunteyarathaḥ
who pressed Arjuna's chariot down with his thumb
saving Arjuna from Karṇa's snake-arrow
M.B Karṇaparva 67 When Karṇa's snake-arrow aims at Arjuna's neck, Kṛṣṇa presses the chariot into the earth with his thumb, lowering it enough for the arrow to take Arjuna's crown instead of his head.
878 ahiśīrṣajit
who overcame the serpent-head (Aśvasena)
M.B Karṇaparva 67 Aśvasena (the cobra-spirit within Karṇa's snake-arrow) is directed at Arjuna; Kṛṣṇa's lowering of the chariot frustrates it; the text identifies Kṛṣṇa as the conqueror of the serpent-head.
879 kālakopapraśamanaḥ
who calmed the wrath of Time
880 bhīmasenajayapradaḥ
who gave Bhīmasena victory
over Duryodhana in the mace-duel
M.B Śalyaparva 57 Kṛṣṇa strategically reveals to Bhīma that Duryodhana's thighs are the weak point and that striking them (contrary to warrior code) is the only way to win; Bhīma follows this and kills Duryodhana.