The secret to the live version intro is using a touch of delay, hitting single notes instead of chords, and throwing an open G string into the riff. Remember to always play the D note on the fifth string with a little vibrato while striking the open D below it for a thicker unison sound. Page revealed this trick in an interview with Guitar World a few years back.
e ------------------------------------------------------------------
B ------------------------------------------------------------------
G --------------------------------------------------0--------------
D--------0--------0------------------------------------0------0---
A -------5--------5----7------------7---------7-------5------5---
E ---7--------7-----------0--0--0-----0--0---------------7------