Jordan Spieth's final round went from bad to worse amid remarkable scenes at Royal Birkdale's 13th hole, putting Matt Kuchar in pole position for Open Championship glory.
Leading by three overnight, Spieth endured a miserable Sunday and Kuchar twice pulled level with his fellow American over the front nine.
Both men parred the first three holes on the way home, but Kuchar gained sole possession of the lead for the first time since Friday when his playing partner messed up dramatically on 13.
An abysmal drive sailed well right of the fairway and Spieth, who put his hands to his head on the tee, eventually took a penalty drop on the nearby practice ground after an age of deliberation with rules officials.
Spieth somehow salvaged a remarkable five in trying circumstances, but Kuchar made par after an excellent approach, putting the 39-year-old one clear at eight under.
Li Haotong could be seen preparing for an unlikely play-off, after shooting 63 early in the day to sit third on six under.
An eagle at 17 took Rory McIlroy to five under, but the Northern Irishman parred the last to end his faint hopes of tying Li's score.
With winds rising and rain around Southport, Li was certainly not out of the running.