South Korean veteran Choi Sang-ho rolled back the years when he fired a six-under-par 66 to grab a three-stroke lead after the first round of the Maekyung Open yesterday. The 50-year-old Choi was in his element at Nam Seoul Country Club, shooting nine birdies against three bogeys to lead another experienced compatriot Cho Chul-sang, who fired a 69 in the US$500,000 Asian Tour event. A group of seven, including Thailand Open champion Richard Lee of New Zealand, 2003 Maekyung Open winner Chung Joon of Korea and Mexican Alejandro Quiroz, trail a further stroke back. Thailand's Thaworn Wiratchant, playing alongside Choi, launched his bid to overhaul compatriot Thongchai Jaidee at the top of the Asian Tour Order of Merit with a 71. Thaworn needs to win a little over US$3,800 this week to knock Thongchai off his perch. Choi's outstanding performance was the story of the day as he maintained the run of good form among the Asian Tour's old guard. Two weeks ago, 42-year-old Wang Ter-chang of Taiwan won the Macau Open while Thai 49-year-old Boonchu Ruangkit challenged at the Philippine Open last week before finishing sixth. One of Korea's top players during his heyday, Choi, who has five titles on the domestic tour, turned in 32 with some sterling golf before battling for an inward 34 where he had two bogeys and four birdies to set the clubhouse target. Cho, 46, made it a day to cherish for the veterans as he registered five birdies against two bogeys in the afternoon to stay within striking range while Park Tae-won, Lee Jung-hoon, Kim Hyung-tae and Kang Ji-man ensured a strong local presence on the leaderboard with matching 70s. Thaworn, winner of the Indonesia Open in March, stumbled on the front nine with successive bogeys on the third and fourth holes but clawed his way back into red numbers with birdies on the 10th, 12th and 16th holes.