Patrick Reed and Abraham Ancer battled it out for the top spot in the final holes of the third round at The Northern Trust.
The two traded places until Reed took the outright lead after 54 holes at the Liberty National Golf Course in the first FedEx Cup Playoff event.
He used five birdies to help counter a bogey on the par-4 15th hole and carded a 4-under 67 on Saturday. It was one stroke off the 66 he carded in both the first and second rounds, but it was enough to gain some ground on Ancer and the rest of the field.
Reed is currently 14 under for the tournament.
Ancer also had a few hiccups with bogeys on both the front and back nine, including the par-4 16th hole which moved him into second place (13 under).
He finished his third round with a 3-under 68.
There's a star-studded group trailing the two leaders, beginning with Brandt Snedeker. The nine-time PGA Tour winner is searching for his first win of the season and used the lowest round of the day, an 8-under 63, to move into a tie for third place (12 under). He is joined by Jon Rahm, who fired a 69 Saturday.
Danny Willett, Justin Rose and Harold Varner III are all tied for fifth (11 under) while Louis Oosthuizen and Rory McIlroy make up a tie for eighth (10 under).
Varner continues to move up the leaderboard and remains in contention going into the final round of the opening playoff event but the others at the top are on a downward trend heading into Sunday. Both Oosthuizen and McIlroy dropped spots in the standings after a number of bogeys plagued their round.
Dustin Johnson, who entered the day as the solo leader, also fell down the ranks. He's in a tie for 10th place (9 under) with Troy Merritt and Max Homa after disaster struck his back nine.
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Johnson carded four bogeys in his last six holes. He ultimately finished the day with a 3-over 74.