World number one Nelly Korda had an opening round to forget at the US Women’s Open as she finished with a 10-over-par 80 including a septuple-bogey on the 12th hole.

American Korda, 25, started the day as the overwhelming favourite to win her first US Open title at Lancaster Country Club in Philadelphia after claiming victory in six of her past seven tournaments.

French amateur Adela Cernousek was among a group of early clubhouse leaders, including American Andrea Lee and Thailand’s Wichanee Meechai, after finishing with a one-under-par 69.

Korda’s challenge is as good as over after her first three holes, which started on the back nine with a bogey at the 10th before she found the water three times on the 161-yard 12th.

Her tee shot sailed over the green into a bunker and her chip from there rolled into a creek fronting the green.

She found the water twice more after penalty drops before finally managing to hit the green with her chip and two-putting for a 10.

“I just didn’t really want to shoot 80 and I just kept making bogeys,” Korda said. “I’m human. I’m going to have bad days. I played some really solid golf up to this point. Today was just a bad day. That’s all I can say.”

Korda, who won this year’s first major at the Chevron Championship, is near the bottom of the leaderboard on 10 over on a day when only a handful of golfers managed par or better.

England’s Jodi Ewart Shadoff went round in two over, while Ireland’s Leona Maguire finished a shot behind on 73.

Scotland’s Gemma Dryburgh and English amateur Lottie Woad – winner of the Augusta National Women’s Amateur – both finished seven over, while England’s Charley Hull was five over.