“Enter Sandman” was the Metallica song whose main riff was inspired by Soundgarden’s Louder Than Love.
Kirk Hammett developed the original guitar idea after being influenced by Soundgarden’s 1989 album. The riff began as a two-bar figure. Lars Ulrich suggested repeating the first bar three times and delaying the second-bar repetition, giving the finished part its distinctive, lopsided momentum.
The instrumental foundation came together quickly, but James Hetfield took longer to settle on lyrics. His initial ideas were darker and more disturbing than the final version. Ulrich and Rock encouraged him to write lyrics that better matched the song’s musical impact.
The finished song became both the album opener and its lead single. The Soundgarden connection does not mean the song is a cover or collaboration; Metallica wrote and recorded it themselves, using the earlier album only as an inspiration for the riff.