Singh's lead dipped from 1.51 points to 0.84 as Woods increased his cushion over third-placed Ernie Els to a nearly a full point.
Following Els, U.S. Open champion Retief Goosen and Masters winner Phil Mickelson held on to the fourth and fifth spots.
Irishman Padraig Harrington climbed two spaces to sixth and was followed by Davis Love III. Mike Weir, the 2003 Masters winner, slipped two slots to eighth.
Sergio Garcia, Adam Scott, Stewart Cink and Darren Clarke maintained the ninth through 12th spots this week. Miguel Angel Jimenez and Chris DiMarco each moved up one space to 13 and 14, respectively.
Kenny Perry dropped two rungs from 13 to 15. Jim Furyk stayed put at 16, while British Open winner Todd Hamilton jumped two to 17th. Stuart Appleby and Chad Campbell slipped one space apiece to 18 and 19, while David Toms held on to the 20th spot in the rankings.