American Webb Simpson scored a course record-equalling 63 to establish a five-shot halfway lead at 15-under in the Players Championship in Florida.
Simpson looked set to post a new record after six successive birdies, but found the water when attacking the island green on 17 and posted a double bogey.
“You’re at TPC Sawgrass, so you know trouble is everywhere,” Simpson said.
Compatriot Patrick Cantlay (68), South African Charl Schwartzel (66) and Danny Lee of New Zealand (66) are in second.
Simpson’s fellow first-round leader, American world number one Dustin Johnson, is now eight shots back after a 71, one behind the world’s seventh-ranked player, Jason Day of Australia (67).
World number three Jon Rahm, of Spain, is a further stroke adrift of Day after a 70.
Fourteen-time major winner Tiger Woods (71) finished on the cut line at one under, as did world number two Justin Thomas (70) and world number four Jordan Spieth (68).
However, Rory McIlroy was among three of the world’s top 10 not to make it – along with Rickie Fowler and Hideki Matsuyama – after a haphazard 74 which included four bogeys and a double.
Ian Poulter is the highest-placed Briton on five-under after shooting a 69, one shot ahead of world number five Justin Rose (72) and Tommy Fleetwood (71).
A further two Englishmen, Matt Fitzpatrick (70) and Ross Fisher (73), made the cut on two under and one under respectively, as did Scotland’s Martin Laird (71).
‘Everything was going in’
Simpson, the 2012 US Open champion, had started the tournament by compiling an accomplished 66 but accelerated clear of the field with a stunning spurt on the back nine on Friday.
The 32-year-old was already five under for his round when he recorded the first of six consecutive birdies on the 11th.
“You start just kind of laughing,” said Simpson, whose halfway score of 15-under matched the tournament record set by Day two years ago.
“Everything is going in. You feel like no matter what, you’re going to make it. It’s rare as a golfer where everything comes together.”
Simpson was 11 under for the day when he stepped on to the 17th tee but his pushed tee shot on Sawgrass’ signature hole clattered against a railway sleeper and ended up in the water.
“I was in between clubs,” he explained. “I tried to smash a sand wedge and blocked it a little bit. It’s a bit of a bummer.”
Simpson righted himself to par the last and equal the 63 previously shot by Fred Couples, Greg Norman, Robert Castro, Martin Kaymer, Day and Colt Knost.
Woods squeezes under cut line
Woods carded two birdies and one bogey in a second round of 71 to finish one under and ensure he would be around for the weekend.
A dropped shot on 18 looked, at one stage, like it would cost the 42-year-old, but he squeezed in under the cut line.
“I was just a touch off today,” he said. “I didn’t make many birdies. I had my chances. I didn’t hit it close enough.
“The course could have been had today. It’s so hot, it’s playing short, the greens are receptive.”
Fellow American Fowler also suffered an early exit after a wayward tee shot at the par-four sixth hole got stuck in a palm tree.
He commandeered a pair of binoculars to help his search but could not confirm that a ball spotted in the tree was definitely his, instead declaring his ball lost and returning to the tee for his third shot.
It was the first of successive double bogeys for the 2015 champion, who finished on one over par.
“Unfortunately, the part of the ball that was showing was just all the white and dimples,” said Fowler. “I couldn’t see any of my markings and so couldn’t identify it, so back to the tee.”