Kiradech Aphibarnrat fired a 9-under 63 on Friday to grab the top spot at the British Open qualifier in Asia.
Aphibarnrat finished at 13-under-par 131 at Amata Spring Country Club.
Three other players -- amateur Hideki Matsuyama, Daisuke Maruyama and Ashun Wu -- also qualified. All four players will be making their British Open debut at Muirfield. The season's third major gets underway July 18.
Matsuyama, a two-time Asia Pacific Amateur Championship winner, carded rounds of 66-69 to finish four back. Maruyama and Wu were one stroke further back at 8-under 136.
Last year, Matsuyama dropped six strokes over the last three holes to cough up a qualifying spot.
Siddikur, who led after the first round, found water on the par-3 17th. He walked off with a double-bogey and that cost him a qualifying spot.