Justin Thomas eagled the par-five 18th hole to grab a share of the lead at the halfway mark of the Tour Championship in Atlanta on Friday.
Playing the difficult East Lake Golf Club, Thomas joined Webb Simpson (67) and Paul Casey (67) atop the leaderboard at seven under through the first two rounds.
Thomas, who is chasing his sixth win of the season, shot a four-under 66 in round two.
The US PGA Championship winner is projected to claim the FedEx Cup with his current standing this week.
Simpson had a three-shot lead entering the 13th hole, but he hit his tee shot well left and then struggled to get back to the fairway.
The American finally finished with a double-bogey six. He ultimately finished his round with five consecutive pars.
Casey started his second round with four birdies in his first 10 holes. Like Simpson, he stalled on the back nine but wound up in great shape heading into the weekend.
Patrick Reed (65), Justin Rose (66), Gary Woodland (67) and Jon Rahm (67) finished round two one shot back at six under.
Rahm still has the opportunity to win both the FedEx Cup and the European Tour's Race to Dubai.
Dustin Johnson (69) and current points leader Jordan Spieth (70) are tied for 15th with first-round leader Kyle Stanley (73) at three under.
In the FedEx Cup top five entering the season-ending event, Marc Leishman carded another 71 and is tied for 24th.
Rickie Fowler's struggles continued, the American shooting a 74 to slip further back to seven over - leaving him 29th in the 30-man field.