He out-scored Justin Rose and Branden Grace, his closest challengers in the money list race, by one and three respectively, while Lee Westwood, Luke Donald and Ian Poulter -- playing for the first time since winning all four of his Ryder Cup games -- had to settle for matching Grace's 70.
Jamie Donaldson was the early pace-setter -- the 37-year-old Welshman shot a course-record 62 to open a four-stroke lead.
Medinah pair Peter Hanson and Francesco Molinari are in joint second place, with world No 1 McIlroy, fellow Ulsterman Michael Hoey and European captain Jose Maria Olazabal -- 492nd in the world -- tied for fourth, five shots back.
After 254 European Tour events without a win, Donaldson finally broke his duck at the Irish Open in July. He is currently 51st in the world rankings and at the end of the year the top 50 earn invitations to the Masters in April.
For a player who has only ever played four Majors and has never been to Augusta, that is a huge incentive.
Donaldson is also on course for his highest finish on the Tour money list, and up for grabs this weekend is a first prize of over £720,000. He has had two 61s on the circuit and this was nearly another, his chip on the short 17th lipping out of the hole.
Nobody has led by more than four after one round all season, and his margin is only two off the all-time Tour record set by Michael Campbell at the 2000 English Open.
Woods, returning to the course where he and Mark O'Meara won the World Cup in 1999, will resume his pursuit of a fourth win of the season in joint seventh place.
"Three or four-under-par was my number on the back nine," the world No 2 said after three birdies in the last four. "I happened to get one more, which was a bonus. It's going to take 20-plus (under) this week to win the tournament; I've got to be aggressive."