"Santo" achieved commercial success mainly in Latin American territories, reaching top 10 in Guatemala, El Salvador, Panama, Puerto Rico, and Peru.

[15] Writing for Remezcla, Isabella Vega thought that "Aguilera has embodied the pop-based vein of reggaeton with the absolute banger, 'Santo'".

[16] In his review for Atwood Magazine, Josh Weiner found the song "fiesta-ready" and cheered its "pure Latin production".

[3] BroadwayWorld's Michael Major praised Aguilera's "unmatched vocals in full force" and thought that the song's "Latin rhythms create the perfect flow that makes an instant hit.

[6] Pip Ellwood-Hughes from Entertainment Focus considered "Santo" "undeniably catchy" and the "EP's strongest moment".

[19] A reviewer from Monitor Latino shared the same sentiment, calling the song "very rhythmic", and noting that it will make "everyone dance to it".

[20] Writing for NEIU Independent, Enrique Cerros named the song "spicy" and thought that it "screams club banger".

[8] Aldo Magallanes of a daily newspaper El Siglo de Torreón called the song "a perfect fusion" and "a powerful performance that, accompanied by Latin rhythms, becomes an instant hit".

[21] American Songwriter's Jacob Uitti positioned "Santo" at number five on his list of the top 10 Christina Aguilera songs.

[10] It is the third installment of the album's visual story-line, a follow-up to the "Somos Nada" video, where Aguilera's lover and business partner was killed after betraying her.

Later Aguilera — dressed in an all-red ensemble donning a flower lip ring — is seen with fairies and forest army all around her.

Rolling Stone's Tomás Mier opined that Aguilera and Ozuna "channel Adam and Eve's wild side" in the music video, and thought that its scenery resembles "dark Garden of Eden".