Scott Hend will take a two-shot lead over Peter Uihlein into the final round of the True Thailand Classic after hitting a two-under-par 70 on Saturday, as Thomas Pieters made his charge.
Australian Hend, runner-up at Black Mountain Golf Club 12 months ago, tied the course record of 64 - set by Uihlein on Thursday - during his second round.
It was more of a mixed bag for Hend in round three as four birdies were negated by two bogeys, but he finished strongly, including a moment of brilliance at the 15th.
Having recorded a bogey at the previous hole, Hend - who finished 22 over for the tournament at last week's WGC-Cadillac Championship - was out of position to the left of the green but he chipped in brilliantly to take the lead.
Another birdie followed at the 17th to increase Hend's advantage, but he missed with an eight-footer at the last that would have stretched his lead further.
American Uihlein followed up his opening 64 with a more modest 71 on Friday, but he remained well in contention thanks for a three-under 69.
Uihlein hit three birdies in an unblemished front nine and, although he dropped a shot at the 12th, a further gain was made at 13.
The biggest mover of the day was Pieters, who hit a brilliant bogey-free 66 to move within three strokes of first place.
The Belgian started his round with back-to-back birdies, and made further gains at the seventh, 10th, 12th and 13th holes to shoot himself into contention having recovered from an opening-round 73 with a 66 on Friday.
Pelle Edberg - who was joint leader with Hend after two rounds - is also three shots back after rescuing a one-over-par 73.
The Swede, who has an official affiliation with the course in Hua Hin, was three over through 15, but made a superb par at 16 and made consecutive gains at the last two holes to remain in contention.