Withdraw Arjuna from the battle by what means so ever that can be done. On Partha being removed, the righteous Yudhishthira is as good as vanquished by you.
स चापक्रम्यतां युद्धाद् येनोपायेन शक्यते। अपनीते ततः पार्थे धर्मराजो जितस्त्वया॥