(Reuters) - World No. 1 Lydia Ko endured one of the worst rounds of her fledgling career on Thursday as the New Zealand teenager limped to a five-over 77 during the first round of the Blue Bay LPGA Tour event in China.

The 18-year-old's struggles on the lengthy Jian Lake Blue Bay Golf Course with its iconic undulating greens left Ko 10 shots off the early pace set by China's Lin Xiyu, who cruised to a bogey-free 67.

"I think today is pretty good round for me," Lin said. "Actually when I played in the practice round, I thought, this place is pretty tough, and also I'm pretty surprised what I'm doing today. So I'm really satisfied with my game today."

The event is the penultimate leg of the LPGA Tour's five tournament Asian swing which has seen Ko retake the top spot in the world rankings from South Korea's Park In Bee after two top five finishes and a win in Taiwan last week.

Following her nine-shot win in Taiwan, Ko did not arrive in China until Wednesday which could have been a factor in her sluggish start following an opening par.

Ko went double bogey, bogey, bogey, bogey from the second with another two dropped shots on the 11th and 12th leaving her at seven-over.

She recovered with two late birdies to sign for a 77, one less than a six-over 78 she carded at the LPGA Tour's Kia Classic in California last year.