KUALA LUMPUR  - Defending champion Choi Na-Yeon kept her cool on the last hole to sink a putt for a share of the lead on the opening day of the Sime Darby LPGA Malaysia Thursday.The South Korean had a blemish-free round at the Kuala Lumpur Golf and Country Club to finish on six-under 65, tieing with Australian veteran Karrie Webb who also had a bogey-free round. World number one Yani Tseng, who was runner-up last year, had a horrendous opening day, shooting a seven-over 78 after carding three double bogeys and four bogeys before saving her round with three birdies.Choi, a crowd favourite, holed birdies on the second, fourth, sixth and eight holes as she blazed through the opening nine holes. She added further birdies on the 12th and 14th holes on the back nine. "I had a great run and after the rain everything just came into place for me," said Choi, who had to endure an hour's delay due to rain before finishing her round."I had fond memories here, having won here last year. I'm sure people expect me to win again and I will try. So far, I think if I just cut it straight and do what I did today, it should be good," she added. Webb was just as consistent, firing birdies on the second, seventh, ninth, 12th, 15th and 17th holes.Taiwanese amateur Min Lee, who held the lead before being overtaken by Choi and Webb, said she hoped for a better performance Friday. "I came into the tournament to gain experience and maybe see a little bit what it's like to play on the LPGA Tour," the 17-year-old said."I didn't expect anything out of it because my ball wasn't striking the fairways and green as how I'd hope. But hopefully tomorrow it will better." The teen is third, together with South Korean Sun Young Yoo and Japan's Mika Miyazato, after the trio fired in seven birdies against two bogeys to lie one shot off the pace.Cristie Kerr of the US carded six birdies to end the day on three-under 68 and is tied for eighth. The six birdies mean she will contribute $1,200 toward the tournament's charity, the Cancer Research Initiatives Foundation (CARIF), after pledging $200 for each birdie. The $1.9 million tournament ends Sunday.