Wozniacki was the runner-up at the season-ending WTA Tournament of Champions in Bulgaria, losing the final to Nadia Petrova 6-2, 6-1. But by winning her semifinal match, Wozniacki gained enough points to pass Marion Bartoli for 10th in the rankings.
Victoria Azarenka wrapped up the year-end No. 1 a few weeks ago. She is the 11th woman to reach that spot since the rankings began in 1975.
Azarenka's point total of 10,595 will be challenged quickly in 2013 when she starts with two early title defenses -- at Sydney and the Australian Open.
Azarenka is 550 points up on No. 2-ranked Maria Sharapova Serena Williams is third with 9,400.
Agnieszka is fourth at 7,425 followed by Angelique Kerber at 5,550.
Just 15 points separate the next three spots in the rankings. Sara Errani is sixth with 5,100 points followed by Li Na (5,095) and Petra Kvitova (5,085).
Samantha Stosur has 4,135 points for ninth place.
Wozniacki comes in with 3,765, edging Bartoli by 25 points.
Petrova, who won the Tournament of Champions, moves to 12th with 3,040 points.
The 2013 WTA schedule begins Dec. 31, 2012, in Brisbane, Australia.
Scarlett Johansson steps out with fiance after pregnancy reveal
Teacher apologizes for showing sexual image of herself in class