Jon Rahm drained a 65-foot birdie bomb on the first extra hole to win the BMW Championship and land his fifth career PGA Tour title at Olympia Fields.
The win vaults the 25-year-old Spaniard up to second behind Johnson in the FedEx Cup standings heading into next week's season-ending Tour Championship, which will decide who wins the FedEx Cup.
The playoff win will come as some relief for Rahm, especially after making his lone bogey of the weekend when receiving a one-stroke penalty after picking up his golf ball before putting a marker down behind his ball on Saturday.
Rahm had fired a best-of-the-day 64 to reach 4-under par for the tournament, and it was a score that was matched by Johnson, who made an incredible birdie putt on the 72nd hole to force a playoff. Watch Johnson's impressive birdie putt on the 18th below...
It marks Rahm's first Playoffs victory but he still remains second behind Johnson in the world rankings.
Joaquin Niemann and Hideki Matsuyama finished in a tie for third on 2-under par, while Tony Finau claimed solo fifth on 1-under par.
Rory McIlroy ended up in a tie for 12th on 3-over par, while Tiger Woods slumped to a tie for 51st on 11-over par - a result that ends his PGA Tour season after failing to make the top-30 that will head to the Tour Championship.
JON RAHM: IN THE BAG
DRIVER: TaylorMade SIM 10.5 degrees; Aldila Tour Green 75 TX shaft
FAIRWAY WOOD: TaylorMade SIM 15 degrees; Aldila Tour Green 86 TX shaft; TaylorMade SIM 18 degrees; Graphite Design Tour AD DI Black 8X shaft
IRONS: TaylorMade P750 (4-PW); Project X 6.5 Rifle shafts
WEDGES: TaylorMade Milled Grind Hi-Toe (52 degrees), TaylorMade Milled Grind 2 (56, 60 degrees); Project X 6.5 shafts
PUTTER: TaylorMade Spider X Chalk
BALL: TaylorMade TP5
GRIPS: Golf Pride MCC Midsize