DHAKA, 27 May 2015 (AFP) - Mamat, a four-time Asian Tour winner, overcame two weather interruptions to take his place atop the leaderboard with six birdies in the $300,000 Asian Tour event at the Kurmitola Golf Club.
O'Toole birdied all the par-fives to tie for the lead in his first-ever Asian Tour event, as India's Amardip Malik and Carlos Pigem of Spain trailed by one shot behind the leaders.
Two Indians, Sanjay Kumar and Sujjan Singh, and Janne Kaske of Finland, were next in line at 68 each, while local hero Siddikur Rahman stumbled to a disappointing 72.
As many as 30 players will complete their opening round early on Thursday after fading light forced play to be suspended late in the day.
Heavy rain stopped play twice in the morning, but Mamat, who rates the Kurmitola course as one of his favourites, stayed calm to charge to the top of the leaderboard.
"The rain delays were a bit frustrating, but I had to make sure it did not spoil my momentum," the 47-year-old said.
"This golf course suits my game a lot. It isn't a power golf course, but more a thinking course. You have to keep the ball in play and hit it straight. This is the type of golf course I like to play on."
Leading scores after round one at the par-71 Kurmitola Golf course:
66 - Mardan Mamat (SIN), Casey O'Toole (USA)
67 - Amardip Malik (IND), Carlos Pigem (ESP)
68 - Sanjay Kumar (IND), Janne Kaske (FIN), Sujjan Singh (IND)
69 - Thammanoon Sriroj (THA), Ajeetesh Sandhu (IND), Om Prakash Chouhan (IND), Mitsuhiko Hashizume (JPN), David Gleeson (AUS)
70 - Thaworn Wiratchant (THA), Masaru Takahashi (JPN), Soom-in Lee (KOR)