REUTERS: Justin Thomas and Jason Kokrak matched the Medinah course record with seven-under 65s to share the first round lead at the BMW Championship on Thursday while a fit-again Tiger Woods struggled to get anything going and finished the day six off the pace.
A shot behind the leading pair were 49-year-old Jim Furyk, Lucas Glover, Brandt Snedeker, Patrick Cantlay and Joel Dahmen, while Rickie Fowler and Australian Adam Scott headline a group of nine on 67, two back on the leaders.
The birdies were flying at Medinah Country Club as an elite 69-player field took advantage of ideal scoring conditions, and both Kokrak and Thomas could do little wrong on the rain-softened course on the outskirts of Chicago.
Thomas turned in an error-free scorecard, highlighted by a storming finish of three straight birdies from the 14th.
Kokrak, who is still chasing his first PGA Tour win, had only once blemish, a bogey at the ninth, to go along with an eagle and six birdies.
Their stellar rounds came despite both players appearing out of touch in their warmups.
The second stop on the FedEx Cup playoffs, only the top 30 ranked players after the BMW will advance to next week's championship at East Lake in Atlanta.
Woods, ranked 38th when the day began, has won two of his 15 major championships at Medinah and he got off to a roaring start with three birdies in his opening five holes, including one at his opening hole for the first time this season.
But the 43-year-old, who pulled out of last week's Northern Trust Open after the opening round due to back pain, saw his hot start cool off quickly.
He added one more birdie to make it four for the round but his card also came with three bogeys.
"Didn't chip it, didn't make that many putts and consequently I'm one under," said Woods, who swung freely and showed no signs of discomfort.
"It's just not sharp, I'm trying to make changes in my swing and it's just not quite there yet.
"I need reps and I just haven't put in a lot of reps.
"I didn't feel any tightness in my oblique at all, I didn't feel any pull and so that was a positive, I just need to clean up my rounds and get going."
World number one Brooks Koepka had a slow start but raced into contention with a four-under 68.
The American was one-over through 11 but went five-under for his last seven holes - an eagle, birdie, birdie run from the 14th pushing him into contention.
Briton Justin Rose, Spaniard Jon Rahm and last week's winner Patrick Reed are also on four-under with Rory McIlroy one further back on three-under 69.
(Reporting by Steve Keating in Toronto. Editing by Peter Rutherford)