Schwartzel, searching for his first title in 20 months after winning the 2011 Masters Tournament, dropped his first bogey of the week at Amata Spring Country Club but a fantastic eagle and three other birdies saw him increase his overnight four-shot advantage.
Sweden’s Daniel Chopra overcame a double bogey as he battled to a 69 to trail a distant second in the Asian Tour’s showpiece while local hope Thitiphun Chuayprakong scrambled to a 71 for third place, six back.
Two closing birdies in front of large galleries pushed Ryder Cup star Sergio Garcia into fourth position following a 68 but he faces an uphill task being eight shots back of the runaway leader.
The 28-year-old Schwartzel, who opened his campaign with successive 65s and leads on 18-under-par 198, is poised to improve on last year’s runner-up finish to Lee Westwood but he is not prepared to pop the champagne yet.
“It’s a game of patience and I just have to go out there to play. If it’s my time, it’s my time,” said Schwartzel, who is seeking his ninth professional victory and his first on the Asian Tour.
“Today felt good. The majority of it was solid. I hit a few bad ones but it was because I was sweating so much. I gave myself a lot of chances especially coming in. 15, 16, 17, 18 … I gave myself chances, could have easily been four birdies. Hit good shots, good putts but it wasn’t meant to be.”
Schwartzel, who is hoping to emulate Westwood’s wire-to-wire victory last year, dropped his first bogey in three rounds after finding the fairway trap on the demanding ninth hole but he quickly reasserted his dominance with a terrific eagle, firing a five iron into the 12th hole and sinking the 12-foot putt. He then rolled in a 10-foot curler on 14.
“It’s unpredictable. I’ve shot two 65s and there is a low score out there. I prefer not to think about it (a winning score). I’m just going to keep playing and see if I can keep shooting a few under par tomorrow,” he said.
“I’m playing well. It’s been a good few weeks as I’m pretty much in control of my golf swing. I can’t ask for more than that,” added the South African, who has finished fifth, third and second in his last three tournaments.
Chopra stayed close to the leader with birdies on one and six but dropped a costly double bogey on the par five seventh hole. He finished strongly with three birdies in his remaining 10 holes.
“I hit a good shot but it clipped the edge of the lip and I made double there (seven). After that I played quite steadily and hung in there nicely," said the Swede, who is a two-time winner on the PGA Tour.
"Obviously my goal is to go out and try to make it uncomfortable for Charl. Nobody wants to see him run away with it. I want to do my absolute best to make it close down the stretch."
Thitiphun, an emerging name in Thai golf, was disappointed he could not finish closer to Schwartzel after a roller-coaster round that included five birdies and four bogeys.
The 20-year-old said: “I made mistakes but these are all part of the game. I’ve been working with my psychologist and I now know there are days when you don’t perform at the level which you want too. I’ve learned to accept that.
“I played perfect golf in the last two days but I’m still happy with the position I’m in. I think a top five finish will be great. Charl played very good but there are so many good players behind him who can shoot a low number. I think the champion will only be decided in the last three holes.”
Garcia reckons Schwartzel would be a hard man to beat. “He played great last year and doing great again. He obviously likes the course. I like the course too but there are a couple of holes which I feel a little bit uncomfortable,” said the Spaniard.
After arriving in Bangkok early Thursday morning for the first round having just completed the Japan Tour Qualifying School, big-hitting Hend, a two-time Asian Tour winner, has moved up the leaderboard nicely with a 69.
“I’m just getting myself into it. Just doing what I can,” he said. “
Charl is playing so well but if you throw something at him and he makes a mistake, there is a possibility. That’s all you can do.
"It’s hard to put pressure on the guy who is eight or nine in front of you. Any pressure that we can put on is the pressure that he puts on himself.”
Defending champion Westwood and reigning Masters champion shot a 70 and 71 respectively for tied seventh place on 209 while current Asian Tour Order of Merit leader Thaworn Wiratchant also carded a 70 for tied seventh position.
Scores after round 3 of the Thailand Golf Championship being played at the par 72, 7453 Yards Amata Spring CC course (a- denotes amateur):
198 - Charl SCHWARTZEL (RSA) 65-65-68.
203 - Daniel CHOPRA (SWE) 67-67-69.
204 - Thitiphun CHUAYPRAKONG (THA) 66-67-71.
206 - Sergio GARCIA (ESP) 69-69-68.
207 - Scott HEND (AUS) 70-68-69.
208 - Masanori KOBAYASHI (JPN) 68-67-73.
209 - PARK Hyun-bin (KOR) 68-74-67, Nicolas COLSAERTS (BEL) 72-67-70, Jbe KRUGER (RSA) 69-70-70, Anirban LAHIRI (IND) 70-69-70, Thaworn WIRATCHANT (THA) 69-70-70, Lee WESTWOOD (ENG) 70-69-70, Bubba WATSON (USA) 68-70-71, Ryo ISHIKAWA (JPN) 70-66-73.
210 - Chapchai NIRAT (THA) 70-73-67, Simon DYSON (ENG) 72-71-67, Hunter MAHAN (USA) 71-69-70.