Massachusetts, August 23: Dustin Johnson took control of the Northern Trust with a seven-under-par 64, while Tiger Woods and Rory McIlroy endured a difficult third round.
Johnson was almost flawless as the former world number one extended his lead to five strokes at TPC Boston on Saturday (August 22).
A two-time winner of the FedEx Cup play-off tournament, American star Johnson carried a two-shot advantage into the penultimate round.
Johnson - 15th in the FedEx Cup standings prior to the opening play-off event - surged clear thanks to an eagle, six birdies and just one bogey in Norton, Massachusetts.
Eyeing a 22nd PGA Tour title, Johnson holed a 40-foot eagle at the last to improve to 22 under through 54 holes, ahead of countrymen Harris English (66) and Scott Scheffler (67).
Louis Oosthuizen (68) is 15 under, while Harry Higgs (66), Daniel Berger (67) and Danny Lee (69) are a stroke further back following day three.
Defending champion Patrick Reed shot a third-round 68 to be 16 strokes off the pace and tied for 51st, a shot behind 2017 FedEx Cup winner Justin Thomas (71).
It was a tough day for Woods and McIlroy as the star pair continued to struggle at the Northern Trust.
After opening with a 68, 15-time major champion Woods has now posted consecutive rounds in the 70s following Saturday's two-over-par 73.
Five bogeys and just three birdies left Woods one under and out of contention, along with reigning FedEx Cup champion McIlroy.
Former world number one McIlroy is a shot worse off following his three-over-par 74, which consisted of two triple bogeys after seeing his chip shot roll backwards into the water on the second hole.