SINGAPORE — Thailand's Chapchai Nirat maintained Zen-like calm to soar to the top of the Singapore Open leaderboard Friday as the $6 million co-sanctioned event suffered a second successive day of frustrating weather disruptions. Chapchai was one of 78 players, including world No. 1 Rory McIlroy, stranded on the course on a storm-threatened Thursday but he returned early Friday to complete a bogey-free six-under 65 for a one-shot lead after the first round. Resuming on three-under after five holes, the stocky 29-year-old added three birdies, including one at the par-five 18th, to move a stroke clear of overnight leader Thomas Bjorn of Denmark before rushing off to start his second round. The Thai canceled out two birdies with as many bogeys in the nine further holes he completed before a tropical downpour brought an early conclusion to the day without a single player in the 150-strong field having completed 36 holes. Chapchai was joined by Simon Dyson at the top of the leaderboard after the Briton recorded four birdies in a blemish-free 13 holes. Dyson will drop at least one shot on resumption after a par putt on his 14th hole shaved the cup shortly before the suspension. McIlroy was even par when he resumed on the ninth hole in the morning and the Northern Irishman was steady for the remainder of his round, birdying the par-four 11th and parring the other holes to register a one-under 70. However, the world No. 1 looked in danger of missing the cut after dropping three shots early in his second round but he steadied the ship and recorded three birdies in four holes to move back under par for the tournament after 30 holes. Italian duo Matteo Manassero and Francesco Molinari moved confidently up the leaderboard to lurk one off the lead with a few holes to play in their second rounds, level with Bjorn, who has only completed 18 holes and did not hit a single shot Friday. McIlroy, watched this week by tennis-playing girlfriend Caroline Wozniacki, admitted the break in play had not hampered his concentration but he was a little disappointed with his display on the greens. Juvic Pagunsan, who lost in a playoff to Gonzalo Fernandez-Castano a year ago, became the second player this week to record a hole-in-one when the Filipino aced the par-three second. Italy's Edoardo Molinari aced the par-three 17th Thursday. Play will resume at 7.30 am (2330 GMT Friday) Saturday with more than half the field yet to start their second rounds. — Agencies