Mbh 6.119.3a

“Then the generalissimo of the Pandava army, viz., the mighty car-warrior Dhrishtadyumna, addressing his soldiers, said, ‘Ye Somakas, accompanied by the Srinjayas, rush ye at Ganga’s son.’ Hearing those words of their commander the Somakas and the Srinjayas, though afflicted with showers of arrows, rushed at the son of Ganga. Thus attacked, O king, thy sire Bhishma, influenced by wrath, began to fight with the Srinjayas. In days of old, O sire, the intelligent Rama had imparted to Bhishma of glorious achievements that instruction in weapons which was so destructive of hostile ranks. Relying on that instruction and causing a great havoc among the troops of the foe, that slayer of hostile heroes, viz., the old Kuru grandsire Bhishma, day after day, slew ten thousand warriors of the Ratha. On the tenth day, however, O bull of Bharata’s race, Bhishma, single-handed, slew ten thousand elephants. And then he slew seven great car-warriors among the Matsyas and the Panchalas. In addition to all this, in that dreadful battle five thousand foot-soldiers, and one thousand tuskers, and ten thousand steeds, were also slain by thy sire, O king, through skill acquired by education. Then having thinned the ranks of all the kings, he slew Satanika, the dear brother of Virata. And the valiant Bhishma, having slain Satanika in battle, felled, O king, full one thousand Kshatriyas with his broad-headed shafts. Besides these, all the Kshatriyas of the Pandava army who followed Dhananjaya, as soon as they approached Bhishma, had to go to Yama’s abode. Covering the Pandava host from every side with showers of arrows, Bhishma stayed in battle at the head of the Kaurava army. Achieving the most glorious feats on the tenth day, as he stayed between the two armies, bow in hand, none of the kings, O monarch, could even look at him, for he then resembled the hot mid-day Sun in the summer sky. As Sakra scorched the Daitya host in battle, even so, O Bharata, did Bhishma scorch the Pandava host.