BANGKOK, THAILAND - DECEMBER 08: Charl Schwartzel of South Africa plays a shot during round three of the Thailand Golf Championship at Amata Spring Country Club on December 8, 2012 in Bangkok, Thailand. (Photo by Athit Perawongmetha/Getty Images)

CHONBURI, Thailand – Charl Schwartzel looked virtually assured of a comprehensive pillar-to-post victory at the Thailand Golf Championship as he cruised into an eight-shot lead Sunday with just over half a round to play.

The South African, who has not won since the 2011 US Masters, birdied the first, fourth and sixth holes to move to 21 under par for the Asian Tour event.

He has been in imperious form this week, dropping just one shot in three-and-half rounds and blitzing a strong field which includes current Masters champion Bubba Watson and world number six and defending champion Lee Westwood.

Home favourite Thitiphun Chuayprakong, 20, led the chasing pack at 13 under and appeared to be set for a strong finish to an impressive week.

Behind him Ryder Cup winner Sergio Garcia bagged two early birdies to move into third place at 11 under. A resurgent Watson was one shot further back, level with defending champion Westwood and Japan's Ryo Ishikawa.

Swede Daniel Chopra, who had pressed Schwartzel for three days, laboured in the heat dropping three shots early in his round and finding the deep rough on the seventh to slip back to 10 under par. – Sapa-AFP