Shane Bertsch hit his tee ball off the ninth tee at 10:00 a.m. (et) Thursday and the 112th U.S. Open began at Olympic Club.

Bertsch, Martin Flores and Tommy Biershenk were the first group out Thursday. They started on No. 9, as opposed to 10, which is the traditional starting tee for the half of the field each week. It was changed to nine this week for logistical reasons.

Skies were gray and temperatures cool, but there was no fog to delay the start of the round.

The fourth group off the ninth tee is Thursday's featured one.

Three-time champion Tiger Woods, five-time runner-up Phil Mickelson and reigning Masters winner Bubba Watson will play the first two rounds together.

The trio will start on No. 9 at 10:33 a.m. on Thursday, then will go off the first tee at 4:18 p.m. on Friday.

Defending champion Rory McIlroy, who set or tied 12 U.S. Open records en route to his eight-shot victory last year at Congressional, will play Thursday afternoon with world No. 1 Luke Donald, and world No. 3 Lee Westwood.

McIlroy, ranked second, and his fellow Europeans will be on No. 1 tee at 4:29 p.m., then begin on 10:44 a.m. on the ninth on Friday.