Paul McGinley was bitterly disappointed to finish 11 shots behind runaway leader Chapchai Nirat in the TCL Classic in China.
The Dubliner could only manage a level par 72 as Thailand's Nirat, 23, scorched to a sensational 11 under par 61 - a new course record.
Nirat hit 11 birdies in an immaculate effort at Yalong Bay Golf Club to open up a three shot lead over Argentina's Rafael Echinique and leave McGInley miles off the pace.
But the Dubliner held his hands up and confessed that his erratic round was simply not good enough.
McGinley groaned: "I played really poorly, I have no excuse. I did well to shoot a 72.
"It was just inconsistent play, I hit a lot of bad shots. I didn't have any control of the golf ball all day.
"I've got to shoot a good score to get back into the tournament, I need to spend some time on the range and find out what I'm doing wrong because I'm not going to shoot that low score with the way I played today. But tomorrow's another day."
Coming off a three week break the Ryder Cup ace, 40, bogeyed the 11th and 15th to slump to two over after starting on the back nine.
A birdie at the 16th gave him some breathing space and he came home in one under par after mixing three birdies and two bogeys on the opening nine.
Waterville's David Higgins also failed to take advantage of low scoring and his 72 left him alongside McGinley and Ian Woosnam in a share of 93rd place.
But Knightsbrook's Damien McGrane hit a three under par 69 to lead the Irish contingent with Michael Hoey a shot further back after a 70 that featured six birdies, two bogeys and a costly double bogey at the fifth.
Yet they were all left spluttering in Nirat's exhaust fumes as the Thai shaved a stroke off the course record set by China's Liang Wenchong last year.
After a birdie at the first, Nirat reeled off eight more birdies in the next ten holes, including four in a row from the fourth.
After going out in six under par 30, he birdied the 10th, 12th, 13th, 16th and 18th for a homeward nine of 31 and the lowest round of his career.
Ranked 310th in the world, Nirat beamed: "I am very happy with the round. I drove well and I was bogey free.
"I played here last year so I am familiar with the course, which helps when driving and putting. There is a lot more rough this year but I made sure I hit straight."
Echenique carded a 64 to sit alone in second place with Taipei's We Teh Lu, Kiwi Richard Lee and South African Keith Horne a shot further back.
Ryder Cup star Westwood shot a six under par 66 to share sixth place on six under after firing an eagle, six birdies and two bogeys.
Westwood said: "I was pretty pleased with the way I played tee to green. I hit a couple of good shots.
"I got a bit lucky at the second but 66 was about the worst it could have been."