Tiger Woods was cruising towards his fourth Target World Challenge title from nine attempts after holding off a mid-round charge by Jim Furyk at Sherwood Country Club near Los Angeles.
Woods has not lost a tournament since turning professional in 1996 when leading by more than a stroke after 54 holes.
But while he maintained his six-shot lead over Furyk by playing the first six holes in two under par to get to 20 under, he faltered with a three-putt bogey at the seventh and another dropped shot at the ninth to see his lead cut to two strokes and raise hopes of an uncharacteristic collapse.
Furyk took advantage of Woods' error at the seventh with a birdie, and while he got to within two of the world number one through the turn, the 385-yard 10th proved to be key.
Furyk was just five feet away in two, but Woods drained a crucial 15-footer for birdie and looked on as his rival three-putted to fall four strokes behind again.
Putting proved to be Pádraig Harrington's downfall in his final event of a tumultuous 2007 season as he racked up his ninth three-putt of the week on the 18th green to close with a 73 that left him provisionally tied for 10th place on two under par.
The Dubliner three-putted six times in the first three rounds and added two more three-putts on the front nine yesterday before three-putting from 20 feet at the last.
"It's been a absolutely tremendous year," said Harrington. "Winning the Open was an unbelievable experience. Even though I three-putted nine times this week it is a good reminder of what I need to work on over the winter. Now it's Christmas and I can sit down and start getting ready for next year."
South Africa's Rory Sabbatini left Woods shaking his head after he became the first player in the history of the event to withdraw before the final round.
A massive 28 shots behind Woods after three rounds, Sabbatini declared he was withdrawing for "personal reasons", while his agent said he had been suffering from shin splints.
"He's messing with the wrong guy," said Fred Couples of Sabbatini's withdrawal. The South African will still receive $170,00 (€117,000) for last place, though Couples added he should donate it to the Woods Foundation.