What once appeared like a walk in the park for Jordan Spieth quickly became anything but. Here's how things ended up at The Northern Trust, where Dustin Johnson rallied down the stretch to catch Spieth and then beat him in a playoff:
Leaderboard: Dustin Johnson (-13, won on first extra hole), Jordan Spieth (-13), Jhonattan Vegas (-9), Jon Rahm (-9), Paul Casey (-6)
What it means: Spieth started the day with a three-shot lead, and his advantage ballooned to five through just five holes of the final round. But Spieth rinsed his tee shot on No. 6 en route to a double bogey, and by the 10th hole Johnson had drawn even. The two remained deadlocked down the stretch, with Spieth making an 18-footer for par on No. 17 only for Johnson to return the favor with an 18-foot par save on the 72nd green. It sent the tournament to overtime, where Johnson birdied the first hole for his fourth win of the season and first since a back injury led to his withdrawal from the Masters.
Round of the day: For the second time in three days, Vegas posted a 5-under 65 to race up the leaderboard. Vegas birdied two of his first three holes and made it around Glen Oaks without dropping a shot, jumping from the fringe of the top 10 into a tie for third to essentially secure a spot on the International Team at next month's Presidents Cup.
Best of the rest: Webb Simpson went low out of the gates, recording birdies on six of his first 13 holes en route to a 65 that matched Vegas and Charley Hoffman for the day's low total. Simpson made his lone blemish on the fifth hole and despite closing with five straight pars he moved up 28 spots into a tie for sixth.
Biggest disappointment: Spieth seemed unstoppable through 54-holes, and his record of closing out final-round leads included only a single blemish. But a few early falters mixed with some impressive play from Johnson, who forced overtime in improbable fashion and then closed out Spieth in style on the first extra hole. For Spieth, it's not of the same magnitude as the 2016 Masters collapse, but it was a surprising result given where he started the day.
Shot of the day: With Spieth already in the fairway on the first playoff hole, Johnson uncorked a 341-yard bomb over the lake that guards the 18th fairway. it proved to be the longest drive of the week and gave the world No. 1 an easy wedge from just 95 yards, which he played to within a few feet to seal the win.
Quote of the day: "It was a little bit easier coming in with a 60 degree here on 18." - Johnson, who had to lay up after driving it into the rough on No. 18 during regulation.