World No.1 Lydia Ko has had a horror three-hole stretch on the back nine, including hitting a ball up a tree, to card a four-over 75 on the opening day of the LPGA event in Texas.

Ko’s score at the Volunteers of America North Texas Shootout left her in a tie for 117th in the 144-strong field.

The 18-year-old New Zealander, who has not missed the cut in her 50 previous LPGA events dating back to her amateur days, will go into day two trailing the leaders by nine shots.

Ko was progressing steadily after picking up two birdies on the front nine at Irving.

However, her round suddenly fell away with a triple-bogey, a double-bogey and a bogey on holes 14 to 16.

At the 14th, she put her third shot up a tree and Australian caddie Jason Hamilton went climbing up the branches to try to find the ball.

Ko said she thought she could get her ball over the tree and on to the green.

“It was pretty close when it hit one of the branches and I thought it would fall down but it ended up getting stuck there,” she said.

“I heard we had to identify the ball so Jason decided to jump up.”

Although Hamilton couldn’t find the ball, a rules official told him everyone knew it was up the tree, so Ko was able to deem it unplayable rather than lost.

As Hamilton made his tricky way back down to the ground, Ko quipped: “You’re really good at monkey bars.”

Topping the leaderboard are the American trio of Cristie Kerr, Juli Inkster and Sydnee Michaels, whose 66s give them a one-shot lead.

Ko went into the event fresh from successfully defending her Swinging Skirts LPGA Classic title in a play-off the previous weekend.

Earlier this week, she said she would donate her winnings from the North Texas Shootout to the Nepal earthquake disaster relief fund.

Australia’s Katherine Kirk, Sarah Kemp, Minjee Lee carded even-par rounds to be five shots off the pace.