The Guitar Riff That Shifted Heavy Metal?

Metallica’s Kirk Hammett thinks the Black Sabbath song “Symptom of the Universe” from the album “Sabotage”, caused a shift in metal that led to both Thrash and the new wave of British Heavy Metal that sprung up in the late ’70s and early ’80s. He says “Just that song in terms of the attitude, the choice of notes, how it was played. It’s just an amazing riff. That riff in itself shifted heavy metal, and I have to give that album and that particular song a lot of credence.” Hard to argue after hearing the opening :40 seconds of the song!