One verse

Srimad Bhagavatam 6.10.29

6.10.29

ते स्वप्रयासं वितथं निरीक्ष्य हरावभक्ता हतयुद्धदर्पा: । पलायनायाजिमुखे विसृज्य पतिं मनस्ते दधुरात्तसारा: ॥ २९ ॥

te sva-prayasam vitatham niriksya harav abhakta hata-yuddha-darpah palayanayaji-mukhe visrjya patim manas te dadhur atta-sarah

te
they (the demons)
sva-prayasam
their own endeavors
vitatham
fruitless
niriksya
seeing
harau abhaktah
the asuras, those who are not devotees of the Supreme Personality of Godhead
hata
defeated
yuddha-darpah
their pride in fighting
palayanaya
for leaving the battlefield
aji-mukhe
in the very beginning of the battle
visrjya
leaving aside
patim
their commander, Vrtrasura
manah
their minds
te
all of them
dadhuh
gave
atta-sarah
whose prowess was taken away

The asuras, who are never devotees of Lord Krsna, the Supreme Personality of Godhead, lost their pride in fighting when they found all their endeavors futile. Leaving aside their leader even in the very beginning of the fight, they decided to flee because all their prowess had been taken away by the enemy.