Mbh 9.61.5a

"Sanjaya continued, 'Upon the conclusion of these words of the intelligent king of the Kurus, a thick shower of fragrant flowers fell from the sky. The Gandharvas played upon many charming musical instruments. The Apsaras in a chorus sang the glory of king Duryodhana. The Siddhas uttered loud sound to the effect, "Praise be to king Duryodhana!" Fragrant and delicious breezes mildly blew on every side. All the quarters became clear and the firmament looked blue as the lapis lazuli. Beholding these exceedingly wonderful things and this worship offered to Duryodhana, the Pandavas headed by Vasudeva became ashamed. Hearing (invisible beings cry out) that Bhishma and Drona and Karna and Bhurishrava were slain unrighteously, they became afflicted with grief and wept in sorrow. Beholding the Pandavas filled with anxiety and grief, Krishna addressed them in a voice deep as that of the clouds or the drum, saying, "All of them were great car-warriors and exceedingly quick in the use of weapons! If ye had put forth all your prowess, even then ye could never have slain them in battle by fighting fairly! King Duryodhana also could never be slain in a fair encounter! The same is the case with all those mighty car-warriors headed by Bhishma! From desire of doing good to you, I repeatedly applied my powers of illusion and caused them to be slain by diverse means in battle. If I had not adopted such deceitful ways in battle, victory would never have been yours, nor kingdom, nor wealth! Those four were very high-souled warriors and regarded as Atirathas in the world. The very Regents of the Earth could not slay them in fair fight! Similarly, the son of Dhritarashtra, though fatigued when armed with the mace, could not be slain in fair fight by Yama himself armed with his bludgeon! You should not take it to heart that this foe of yours hath been slain deceitfully. When the number of one's foes becomes great, then destruction should be effected by contrivances and means.