Second half of sloka21 and sloka22
[Sanjaya is narrating the war as it happens to Dhridhrashtra and he says] Arjuna taking his bow tells these words to Sri Krishna" Achyutha, take my chariot between the two armies and place it there so that i can see those who have come to fight this war."
Here Arjuna orders and calls Sri Krishna Achyutha.
He orders the Bhagwan rather than requesting and this shows the intimacy between the two and also the extent to which the Lord will serve His bhakthas. Achyutha in Sanskrit means not letting down. here are two interpretations 1.He does not lets down His bhakthas and 2.He remains steadfast with His characters, words and actions.
Sanjaya and Dhrdharashtra were disciples under the same guru and once D asks Sanjaya as how even though both are learning simultaneously Sanjaya is clear in grasping and in understanding conceptions while D is not. o this it seems Sanjaya replied that if D will not get angry he will tell and says because Sanjaya does not have any cheating or deceiving mind. hat is he means D is possessing these evil qualities.
hat is why in the very first sloka D asks Sanjaya what do my children and Pandu's children are doing in Kurukshetra battlefield. Here actually D unintelligently conceals his desire to see Kauravas vanquish Pandavas. Sanjaya while narrating immediately tells that as Sri Krishna and others blow their conches the sound shatters the minds and hearts of Kauravas. D does not see the point as he is having a biased mind. Now also he does not understand the implication of the word Achyutha. hat is why at the end he tells D bluntly that victory is there where krishna is there. [Yatra yogeswara Krishno yatra partho dhanurdharaha tatrashri vijayo bhutir dhruva neethir mathir mama]