Seven shots ahead at the start of play, six shots ahead after 10 holes, one shot up on the 15th tee; it seems astonishing that Koepka’s successful defence of the Wanamaker Trophy was ever in doubt. Yet in doubt it was as a supposed formality lurched towards disaster.

The 29-year-old was in grave danger of delivering one of the worst capitulations in major history during a Sunday afternoon run in which he bogeyed four holes in a row from the 11th. Dustin Johnson, playing ahead of him, appeared in the rear-view mirror. The only thing missing was a reading of the typically unflappable Koepka’s heart rate.

Koepka was to prevail, by two at eight under par, which left one pondering what all the earlier fuss was about. Johnson, having reduced that pre-round advantage by six, dropped shots on the 16th and 17th. Koepka’s par on the 15th stopped the bleeding. His missed par putt from 4ft at the penultimate hole did not matter. Koepka took to the 18th with a two-shot lead and managed to fall over the line in the manner of a broken marathon runner from there.

Koepka has now won four majors in eight starts and the space of 23 months. He is again the world’s top ranked player. A relieved Koepka said: “I am just glad we didn’t have to play any more holes. That was a stressful round of golf. The wind was up, DJ was awesome but I’m glad to have this trophy back in my hands. I don’t even know if I dreamed of this. I’m still in shock.”

Johnson will be criticised by some for blinking just when Koepka’s grasp on the trophy had been weakened. At least Johnson made it interesting. He was the only one of the final 24 players in the field under par for his round. Johnson’s 69 afforded him a four-stroke cushion from those tied third.