"Sly" reached number 24 in the United Kingdom, becoming Massive Attack's fourth top-40 single there.

After hearing her first album Now is Early, and being suitably impressed by it, Massive Attack chose Nicolette to appear on Protection.

[citation needed] Push from Melody Maker felt releasing the song as the first single from the Protection album was "the smartest choice", praising the "dreamy-voices" by Nicolette.

"[2] Dele Fadele from NME wrote, "'Sly' finds Nigerian-born Nicolette trilling on in a sultry and wistful manner about time-travel, fate and destiny whilst the string-laden, mid-tempo backdrop conjures up images of the South Seas Pacific and somewhere more devastated and ominous.

The overall effect is of putting your ears close to a sea shell and hearing clear, chiming, harmonic bells; as dazzling as that.