The commentators were left stunned, calling it an “incredibly bad shot” and “a shot you’d expect to see from a 15-handicap”.
“Goodness, I can’t even recall the last time she had a quad. It’s just a genuine shock to the system,” said one of the commentators.
“That’s the worst shot I’ve ever seen her hit with a six-iron. Just mind-blowing, really, that she would make a mistake like that.”
Aside from the par-three shocker, Ko’s round was solid, with two birdies – including an immediate bounce-back on the par-five sixth, but she battled coming home with bogeys on the 12th and 18th to finish well off the pace.
Fellow Kiwi Amelia Garvey also struggled in a strange round, being five-over through five holes before briefly bouncing back to get to three-over with three holes to play, only to bogey the final three holes to finish at six-over in a share of 114th.
Leading the way are world No 8 Hyo Joo Kim and No 9 Xiyu Lin at four-under, while Ireland’s world No 10 Leona Maguire has continued her hot form to sit at three-under alongside her amateur compatriot Aine Donegan, as well as Allisen Corpuz, Bailey Tardy, Nasa Hataoka and Hae Ran Ryu.
With only mild wind and a marine layer over the Monterey Peninsula, this was the gentle version of Pebble Beach. But this also is a US Open, and it didn’t take much to take a toll, with only 20 players under par.
The biggest surprise was Jin Young Ko, the No 1 player in the world who made only one birdie in her round of 79. She had plenty of company.
Nelly Korda, the No 2 player in the world who missed the cut at the PGA two weeks ago, began her round by sending her opening drive over the cliff and onto the beach at No 10 for a double bogey. She opened with a 76, while world No 4 Lilia Vu had a 79 and No 7 Atthaya Thitikul a 76.
Rose Zhang, the 20-year phenom who started as favourite for the event, began with a two-over 74 to sit in a share of 39th.