When they attacked Savyasachi (Arjuna) from above, they were stopped by his net of arrows. While they attacked him from all sides on earth, they were stopped by his Bhala (weapon).
ऊर्ध्वमाक्रममाणाश्च शरजालेन वारिताः। विसर्पमाणा भल्लैश्च वार्यन्ते सव्यसाचिना॥