Azarenka protected her top ranking by winning the Australian Open Jan. 26. She was atop the rankings for 19 weeks early in 2012 and returned to No. 1 last summer and had held the position for the last 31 weeks.
Her 50-week run at No. 1 is 10th most in WTA history. Carolina Wozniacki is ninth on the chart with 67 weeks.
Li Na's 6,255 points is fifth most and Angelique Kerber comes in sixth at 5,695 points followed by No. 7 Sara Errani (4,795). Petra Kvitova has 4,285 points for eighth but is only 55 points up on No. 9 Samantha Stosur. Marion Bartoli (3,740) completes the Top 10.
Mona Barthel beat Errani in Sunday's finals of the 21e Open GDF Suez event in Paris. Barthel goes from 45th to a career high No. 28 in this week's rankings.
Maria Kirilenko defeated Sabine Lisicki for the PTT Pattaya Open title in Thailand last week. Kirilenko improves two spots this week to No. 13 and Lisicki is up 12 places to 40th.
There is a break in the WTA schedule this week for the quarterfinals of the 2013 Fed Cup. The series to be played Saturday and Sunday are: Australia at the defending champion Czech Republic, the United States at Italy, Japan at Russia and the Slovak Republic at Serbia.