Kiradech Aphibarnrat held his nerve to sink a lengthy birdie putt at the last and take the outright lead at the KLM Open after three rounds.
The Thai shot a bogey-free 66 to go 14 under for the tournament in the Netherlands and move one ahead of Romain Wattel, who went round in two fewer strokes to complete a stunning blemish-free scorecard.
Overnight leader Joel Stalter slipped two shots off the pace, with Lee Westwood headlining a group of players one stroke further back at 11 under.
Aphibarnrat's place at the summit was secured by a 25-foot putt at the 18th, but closest challenger Wattel was still content with his day's work.
"I'm very delighted, I played very good," the Frenchman, who has not recorded a top-20 finish this season, told the European Tour website.
"I just tried to play my own game and I made some good putts.
"The game, it's just up and down. I've been doing my best this year, but it hasn't been enough.
"I've been working with my coach and changed many things, but when you work a lot you don't always get what you expect."
The rain-affected second round had to be completed on Saturday morning and by the midway point, Stalter shared the lead with Joakim Lagergren, who finished the day level with Westwood and Sebastian Heisele.