Tiger Woods is in danger of surrendering his position as world number one to Phil Mickelson in two weeks' time.
Woods has been top for 198 consecutive weeks but his commanding lead was whittled away as he spent eight months on the sidelines following reconstructive knee surgery after his U.S. Open triumph in June.
The number one is now only 0.20 points ahead of his fellow American and if Woods fails to win this week's Arnold Palmer Invitational in Florida, victory for Mickelson at the following week's Houston Open would put the left-hander top.
Mickelson, who has never been number one, is taking this week off.
"It is astonishing someone can effectively take around a year off, because after the U.S. Masters in April he only played again at the U.S. Open in June, and still hang on to the number one spot," Ian Barker, who manages the official rankings, told Reuters Monday.
Woods was also top for 264 consecutive weeks between 1999-2004.
The next longest run is Australian Greg Norman's 96-week spell as world number one from 1995-97.