Om Namo Venkatesaya

Anni Manthramulu Yindey Avahinchenu       
Vennatho Naku Galigey Venkatesu Manthramu

Naradudu Japiyinchey Narayana Manthramu
Cherey Prahladudu Narasimha Manthramu
Kori Vibhishanudu Chekoney Rama Manthramu
Veray Naku Galigey Venkatesu Manthramu                              | Anni |

Rangagu Vasudeva Manthramu Dhruvudu Japiyinchey
Angavinchey Krishna Manthramu Arjunudu
Mungita Vishnu Manthramu Mogi Sukudu Pathiyinchey
Vingadamai Naku Nabbay Venkatesu Manthramu                     | Anni |

Inni Manthramula Kella Indira Nadhudey Guri
Pannina Didiyey Para Brahma Manthramu
Nannu Gava Galigeybo Naku Guru Deeyaganu
Vennela Vantidi Sri Venkatesu Manthramu                                | Anni |

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)