"I'm going to try and keep stride with Tiger and maybe we can have another shot at it on Sunday like we did last year," said Mickelson.
The event features nine of the top-10 players in the world.
No. 2 Vijay Singh (67) is part of a group tied for 12th place. No. 3 Retief Goosen shot a 2-under 70 to tie for 61st. No. 4 Ernie Els, the 2002 champion, managed an even-par 72 and is part of a group in 98th place.