Om Namo Venkatesaya
Anni Manthramulu Yindey Avahinchenu
Naradudu Japiyinchey Narayana Manthramu
Rangagu Vasudeva Manthramu Dhruvudu Japiyinchey
Inni Manthramula Kella Indira Nadhudey Guri
Listen to Sankirtana
This is a composition of Tallapaka Annamcharya. In this composition Annamcaharya says that All Mantras are in Venkatesu Mantra which he acquired as a child.
Naarada chanted Narayana Mantra, Prahlada-Narasimha Mantra, Vibheeshana-Rama Mantra, Dhruva-Vasudeva Mantra, Arjuna-Krishna Mantra, and Sage Suka-Vishnu Mantra.
Lord Vishnu is the focus for all the Mantras and the Vishnu Mantra is the Para Brahma Mantra. Since Lord Venkateswara is Vishnu, Annamacharya deduces that all Mantras are in Venkatesu Mantra which is as cool as the Moonlight. (In another composition Annamacharya describes the qualities of Moonlight, which explains why Annamacharya established similarity between Venkatesu Mantra and Moonlight)