A deep devotee of the Lord by name padmanabhan came up to the hills and was performing penance for several years. He eat fruits in the beginning and drank only water later. Years later he was living on the air only. His penance became steady.
One day the Lord appeared before him and requested him to ask for any boon. But Padmanabhan wanted only to continue his penance for his entire life-time without any interruption. Granting that the Lord disappeared.
As Padmanabhan was continuing his penance, a demon saw him one day. He came neared him to swallow him. Terrified by this Padmanabhan remembered the Lord at once.
The Graceful Lord sent his Sudharsana Chakra. The vibrant disc Chased the demon's head in to pieces. Since the charka appeared near the lake there it was know as Chakra Thirtham.