Azarenka is the 11th player to finish atop the world rankings. She was 69-10 this year and won six titles. She opened the year by winning her first four events -- at Sydney, the Australian Open, Doha and Indian Wells, Calif. She collected titles at Beijing and Linz, Austria, later in the year.
She also was second three times. One of those was in the finals of the U.S. Open against Serena Williams.
Maria Sharapova, who was No. 1 for four weeks in the summer, could have caught Azarenka at the WTA Championships if Azarenka won fewer than two matches and Sharapova won the title. Sharapova finished second to Williams.
There were slight changes this week to the women's Top 10 with one tournament -- the Tournament of Champions in Bulgaria -- left on the 2012 WTA calendar.
The first five in the rankings are the same as before the WTA Championships with Azarenka in first with 10,595 points followed by Sharapova (10,045), Williams (9,400), Agnieszka Radwanska (7,425) and Angelique Kerber (5,550).
Petra Kvitova was sixth last week but she became ill during the WTA Championships, which she won in 2011, and played just one match. Although the point totals are very close, she slips to eighth, allowing Sara Errani to mark a career high with the No. 6 ranking and Li Na to move to seventh. Errani has 5,100 points, Li 5,095 and Kvitova 5,085.
Samantha Stosur is ninth with 4,135 points and Marion Bartoli is 10th with 3,740.