Runaway leader Lee Westwood saw his 11-shot lead cut to four by Masters champion Charl Schwartzel at the Thailand Golf Championship.
Westwood's one-over 73 in the third round on Saturday was in stark contrast to his stunning career-low 12-under-par 60 in the first round and eight-under 64 in the second.
The impressive Schwartzel carded a back-to-back six-under 66s to slash the world number three's lead at the top at the season-ending $US1 million Asian Tour event.
Schwartzel's only slip-up came with a bogey at the par-four 18th after he had reeled off seven birdies, four of which came on the front nine.
"At least there's light at the end of the tunnel now," the South African said. "Four shots is not much out there. I've been playing really well and I can shoot a low score on this golf course. I felt I should have shot a 63. I felt like I left putts out on 12, 13 and 14. Not a very good bogey on 18 but I feel like I can shoot low and that's what I need."
American Michael Thompson's 69 saw him in third, some seven shots off the leader Westwood, whose round included some uncharacteristically wayward shots.
The Englishman, who equalled the Asian Tour's 36-hole record with 20-under-par in the opening two rounds, made his first bogey of the tournament on the par-five second before dropping further shots on the sixth, 16th and 17th.
But with a four-shot lead, the 38-year-old was still confident of securing his fourth title of the season.
"(I had) a few bad breaks … if you had offered me a four-shot lead on Thursday morning I would have taken it," Westwood said.
"After a 60 and 64, you're probably going to be disappointed with the third round but like I said, a four-shot lead into the last round is a good position to be in. It drains you (to be leading) but it's a better position to be leading obviously other than to chase."
The Netherlands' Guido Van Der Valk gave himself every chance of earning a full 2012 card with a 66 which propelled him to fourth place.
Englishman Simon Dyson is a shot further back at nine-under while India's Jyoti Randhawa moved up to eight-under with a 65.