PGA Tour winner Mackenzie Hughes thought he had made a birdie on the final hole of his first round at the Farmers Insurance Open.
But the Canadian had played the wrong ball, meaning he actually carded a double-bogey seven.
Hughes was four-under heading into the ninth, his final hole, after a solid round on the North Course at Torrey Pines when he hit his second shot short and left.
A marshal marked where the ball finished and Hughes chipped to six feet – only discovering when he went to mark his ball that it wasn’t actually his.
The 31-year-old's ball was in fact just eight feet from the pin, and would have given him a decent look at eagle.
Because it counted as a breach of Rule 6-3c, Hughes had to go back and replay the chip, turning what would have been a simple birdie into a frustrating double-bogey.
Well I hit my second shot on the par 5 9th short left of the green. I went to where it was marked with a flag and hit my chip to 6 feet. When I marked it I realized it wasn’t my ball. Turns out it was about 8 feet from where the flag was. Went from maybe 4 to 7 pretty quick. https://t.co/jvQRuu95fh— Mackenzie Hughes (@MacHughesGolf) January 27, 2022
It also means that rather than being four shots behind leader Billy Horschel at the start of the second round, he began seven back.
The drama only emerged when Hughes responded to a fan on Twitter.
“Well I hit my second shot on the par five ninth short left of the green,” he explained.
“I went to where it was marked with a flag and hit my chip to six feet. When I marked it I realised it wasn’t my ball.
“Turns out it was about eight feet from where the flag was. Went from maybe four to seven pretty quick.”
The incident is the second piece of misfortune to befall Hughes at Torrey Pines inside 12 months.
He was tied for the lead at last year’s US Open when his ball came to rest in a tree, costing him a one-shot penalty.