|If Schwartzel can extend his third round form there will be a dramatic finish to Thailand Championship [AFP]
World number three Lee Westwood suffered a slump in form as his huge lead of the Thailand Golf Championship was slashed to four stokes by surging South African Charl Schwartzel on Saturday.
An erratic day for Westwood saw him card a third round of 73, 13 shots worse than his stunning opening round 60 which helped him to an 11-stroke lead at the halfway point.
U.S. Masters champion Schwartzel made four birdies in his first five holes on his way to a second successive 66 at the Amata Spring County Club, paving the way for a crunch final day at the $1 million Asian Tour event.
Westwood had not carded a bogey in his opening two rounds but four arrived on Saturday as his dazzling form from earlier in the tournament disappeared.
The Englishman, whose 64 in round two gave him a share of the Asian Tour's lowest-ever 36-hole total, said he still had the upper hand and the pressure was on his rivals to overhaul his lead and deny him his third Asian victory this year.
"A lot of people are going to think you're going to shoot a 60, 62 and 64 every day but I'm afraid golf isn't like that,"
Westwood told reporters.
"I hit a few good shots in between but I didn't make puts when I needed to. It was one of those days, a few bad breaks but if you'd have offered me a four-shot lead on Thursday morning, I'd have taken it.
| Westwood carded his first bogeys during the third round [EPA]
"I can stretch my lead and people have to put their foot down and that's where you can make mistakes."
Schwartzel was in confident mood and kept his cool on a sweltering day with American Michael Thompson creeping up on him on the back nine to finish on 69 for third place, seven strokes adrift of Westwood.
After a rough start on the opening six holes, Westwood got back on track, matching Schwartzel stroke for stroke for the
next nine holes before two unlucky bogeys on the 16th and 17th.
The South African held his game together right up to the end but botched a simple putt on the 18th and watched his ball grind agonisingly to a halt on the edge of the hole for his only bogey of the day.
He admitted he would need a first-class performance and an unlikely Westwood meltdown for him to win the title.
"I made four birdies in a row and he wasn't getting anything at all. You sense all of a sudden, the tide has changed, the lead getting shorter and shorter and that has to affect you. You wouldn't be human if it didn't," Schwartzel said.
"I really have no alternative, I need a good score and that's the bottom line. We all know Lee is a good player. It's
out of my hands... but I've won two or three tournaments from four shots behind, I've done it before but I don't know the