Former world number one Jordan Spieth showcased his stellar putting game as he moved into a four-way tie for the lead after the second round at the Northern Trust.
Spieth reeled off five successive birdies from the 10th hole on the back nine to card a five-under-par 65 and earn a share of the one-stroke lead alongside world number one Dustin Johnson, Rickie Fowler and Jhonattan Vegas at the halfway stage of the year's first FedEx Cup Play-offs event.
The three-time major champion produced a putting masterclass following the turn, having only posted a birdie and bogey from his opening nine holes at Glen Oaks Club on Friday.
Spieth - who won the FedEx Cup in 2015 - gained strokes at the 10th, 11th, 12th, 13th and 14th holes before he dropped a shot at the 15th, only to recover immediately with another birdie - a 40-footer at the 16th as he surged to six under after two rounds.
It is a logjam of the highest quality atop the leaderboard, with Johnson, Fowler and Vegas also six under heading into Saturday's penultimate round.
After opening with a 65, Johnson shot a one-under-par 69, which included three birdies and two bogeys.
Fellow American Fowler also improved in the standings thanks to his four-under-par 66, while Venezuela's Vegas posted a flawless 65.
American duo Matt Kuchar (64) - who birdied six of his last nine holes - and Bubba Watson (68) are a shot off the pace in Old Westbury, New York, while Justin Rose (68), Jon Rahm (68) and Russell Henley (72) are a stroke further back.
Jason Day - winner of the tournament in 2015 - struggled on Friday following his one-over-par 71, which left him six shots adrift.
Day birdied three consecutive holes during a flawless back nine but the damage was done before the turn, when the Australian bogeyed his first hole and double-bogeyed the third and seventh.
Reigning FedEx Cup champion Rory McIlroy, meanwhile, recovered from his poor start with a 68.
With three birdies and a bogey, Northern Irishman McIlroy improved 48 positions to be one over at the midway point of the event.
Meanwhile, the likes of Hideki Matsuyama, 2014 FedEx Cup champion Billy Horschel, 2011 FedEx winner Bill Haas and Zach Johnson missed the cut.