SPRINGFIELD, New Jersey (Reuters) - Young Argentine Emiliano Grillo shot into the lead with a birdie barrage that put him four-under at the turn and eight-under for the tournament late in Friday's second round of the PGA Championship.
The 23-year-old Grillo, who said after his 66 on Thursday that putting was the weakest part of his game, belied that with four birdie putts in his first nine holes at Baltusrol on Friday, including a a 40-foot bomb that fell in at the 15th.
Grillo, who began his round at the 10th, made his move in warm sunshine that dried out the Tillinghast layout after a rainy start to the day.
One stroke behind Grillo was overnight leader Jimmy Walker, who improved by two shots on Friday with nine holes to play after opening with a 65.
Leading in the clubhouse on six-under 134 was British Open champion Henrik Stenson, who carded a second successive 67 to put himself in the chase for a second successive major title.
The Swede, who fired a sensational final-round 63 to outduel Phil Mickelson at Royal Troon two weeks ago and set a British Open scoring record with a 20-under total, was pleased.
"Of course, I'm very happy to be able to follow up the success at Troon with a couple of strong rounds here and be in good position," said the 40-year-old Stenson.
"We know it's a marathon, not a sprint. It's all about being there for Sunday afternoon, and so far, so good."
One stroke behind the big Swede on five-under were 2010 PGA winner Martin Kaymer of Germany (69) and Patrick Reed (65).
The second round began ominously when pouring rain led to a 41-minute suspension of play a little more than an hour after the first tee shots of the day.
That downpour followed an inch (2.54 cm) of rain overnight that made the tricky Baltusrol greens more receptive for approach shots, yet players said the greens were still fast.
Thirty-five players bettered par in the opening round and the early starters kept up that pattern, crowding the leaderboard before the afternoon wave, whose tee times were pushed back 45 minutes due to the rain delay.
Stenson, who started at the 10th, struggled at first with bogeys at 12 and 13 but did not stay down for long, snapping back with an eagle-three at the par-five 18th.
"I hit a really good 3-wood in there," said the Swede. "It landed perfectly just at the front edge and trickled up to three feet."
Three birdies over his second nine pushed him up the leaderboard.
Late starters Robert Streb (through seven holes) and Englishman Andy Sullivan (six) were tied for sixth on four-under, one shot ahead of a large group on three-under that included American world number three Jordan Spieth.
Spieth got off to a sizzling start with three birdies in his first four holes with a bogey in between after starting the day from the 10th.
Back-to-back birdies on the par-fives at 17 and 18 lifted him to four-under for the day and the tournament, but he gave a stroke back to finish with a 67 for 137.
"On the greens they were a wicked two feet faster ... even after all that rain," said Spieth. "They were so smooth, they were pure and they were really nice to putt on.
"But, man, I hit almost every mid-range putt I had a good two to four feet past the hole."
Spieth said he has not quite solved the subtle breaks on the Baltusrol greens but remained optimistic.
"I'm hitting the ball fantastic. I just can't get a putt to go in outside 10 feet," he said.
"And from 10 to 20 feet, (given) the amount of opportunities I've had that aren't that difficult, up to my putting standards I would be five, six, seven strokes better right now."
Reporting by Larry Fine; Editing by Mark Lamport-Stokes