Webb Simpson romped into the clubhouse lead but all eyes turned to Tiger Woods as he opened his bid for an eighth tournament victory on the South Course at Firestone with a sweet 66.
Tiger has not won here since 2009 but, ominously for the opposition, yesterday was his best first round at the Bridgestone Invitational World Golf Championship since 2005.
Woods trailed Simpson by two after the 2011 US Open champion took advantage of greens softened by heavy overnight rain to post a six-under-par 64 in his first competitive round at Firestone.
Henrik Stenson followed on from an impressive second place in last month's Open at Muirfield with a bogey-free 65.
Few players have struck the ball as consistently or better than Stenson from tee to green on the PGA Tour this season, credit for which should also be paid to Pete Cowen, the swing coach he shares with Padraig Harrington, Graeme McDowell and several others.
World number three Rory McIlroy, looking to replicate the fifth-place finish of last year which kickstarted his season, is within touch of the leaders on level par.
The Holywood ace slipped to two over par with a double bogey on the 10th, but then birdied the 12th, 13th and 15th and also missed from five feet for another on the 14th.
But the 24-year-old finished with a bogey to end his opening round on a disappointing note.
"I thought I drove the ball, for the most part, very well," said McIlroy.
"Some of my iron shots were very nice too. If I can keep hitting the fairways and hitting good iron shots I will get chances for birdies and that's all I can ask of myself.
"I felt like I held some good putts out there too. I did some good work with Dave Stockton over the last couple of days and I'm starting to feel more comfortable with my putting."
Fellow Ulsterman McDowell and Shane Lowry found the going difficult as the yielding fairways on the 7,400-yard South Course played to their full length.
Though Portrush man McDowell signed for a one-over 71, he opened brightly, ramming home a 26-foot birdie putt on his second hole, the 11th.
Yet, after going through the turn in one-under, McDowell hit his tee-shot at the first into a near-impossible lie in a right fairway bunker and wound up with an untidy double-bogey six.
A facile two-putt birdie four at the second and a bogey at five after hitting his tee-shot into cloying rough to the right of the fairway left McDowell seven off the pace and he went straight to the range afterwards to work on his swing with Cowen. "My swing's a little inconsistent as you'll see from my scores this season," he said. "I just seem to be jumping from one swing thought to another. Maybe I know a little to much about my swing."
However, Lowry then dropped three shots after missing a series of fairways and greens in a frustrating four-hole stretch through 17. So he ended-up signing for a 72.
Lowry hit just eight of 18 greens, eight fewer than Woods, playing his first competitive round of golf since the Open.
"I'm very pleased with that. I hit it pretty good today, just controlled it. I missed a few putts today from about 15-foot range but overall it was a pretty good day," said Tiger.