By DOUG FERGUSON

The Associated Press

A back corner of the locker room at the Byron Nelson Championship is reserved for past champions, the perfect place for an impromptu duel between Tiger Woods and Phil Mickelson.

Woods was changing his shoes and chatting with a few reporters last year when Mickelson walked into the room. Before long, two of the best players in golf starting lobbing school-yard challenges at each other, everything from racquetball to tennis, from basketball to swimming.

When and where their rivalry began is hard to pinpoint. They have been linked so often that Mickelson was surprised to hear the first time he and Woods played the same tournament was the 1993 Nissan Open.

They never have met in a playoff, as Jack Nicklaus and Arnold Palmer did at the 1962 U.S. Open. And for the last several years, Mickelson merely has been part of the rotation of rivals to Woods, sharing time with Ernie Els or David Duval or Vijay Singh.

That’s no longer the case.

Woods-Mickelson figures to be the main event at the U.S. Open when it starts Thursday at Winged Foot.

They are Nos. 1-2 in the world ranking. Their peers say they have the most raw talent in the game. They have won four of the last five majors, with Mickelson capturing the last two. And for the first time since Woods’ record victory in the ’97 Masters, he might not be the favorite at a major championship.

“There’s clearly two guys out here doing the thing, doing the damage,” Paul Azinger said. “I think Phil Mickelson is the best shotmaker on tour right now. I think he’s the most confident player in the world. And I think he’s the man to beat.”

How Woods will perform is a mystery.

He has been coping with the May 3 death of his father, and Woods has not played since the Masters. The nine-week break is the longest of his career.