In a span of three holes around the turn at Medinah, Justin Thomas' six-shot lead shrunk to two.
Thomas answered with two clutch wedge shots, two big putts and sailed to a 4-under 68 to secure a three-shot victory at the BMW Championship over Patrick Cantlay, who gave him a battle to the end with a 65.
His first victory since the World Golf Championship at Firestone last year moved him to the top of the FedEx Cup going into the Tour Championship, where he will start the tournament at 10-under par with a two-shot lead under the new scoring format as the final 30 players chase a $15 million first prize.
Cantlay, who made four straight birdies around the turn, secured the No. 2 position and will start at 8 under. Brooks Koepka will be 7 under, a staggered start all the way down to even par for the final five players.
The Championship field will not include Masters champion Tiger Woods, the defending champion.
Woods was a long shot going into the final round to crack the top 30, and he closed with a 72. East Lake was his first victory in five years, capping his return from four back surgeries, a special moment replaced some six months later by his Masters victory.
Hideki Matsuyama took the 36-hole lead with a 63 until falling back with a 73. He responded with another 63 to finish alone in third, making him one of three players who moved into the top 30 to reach East Lake. The other was Jason Kokrak, but only after J.T. Poston made bogey on his final hole.
The final day to earn the eight automatic spots on the Presidents Cup changed nothing for either team.
Bryson DeChambeau held onto the final spot for the Americans when Tony Finau, who needed to finish alone in third, closed with a 69 and finished fourth. Jason Day failed to work his way into an automatic spot for the International side.