Conversation so far:
Where was Phil Michelson's first major win?
Mickelson's first major championship win came in his thirteenth year on the PGA Tour in 2004
Where was Phil Michelson's second major win?
Mickelson captured his second major at the PGA Championship at Baltusrol.
Did Phil Mickelson win anything else during 2004 until 2006?
Phil Mickelson captured his third major title the following spring at the Masters at the 2006 PGA Tour.
Was Phil Michelson's third major title at the Masters his final victory?
No, Phil Mickelson continued playing after the Masters at the 2006 PGA Tour.
Did Phil Mickelson play against Tiger Woods at the 2006 spring Masters?

Question: Who did Phil Michelson play against?
Self-contained rewrite: Who did Phil Michelson play against at the Masters of the 2006 PGA Tour?