Wozniacki won the BGL BNP Paribas Luxembourg Open and the 280 rankings points that go with it. But last year at this time she won the Kremlin Cup in Moscow. First place in Moscow brings 470 points so Wozniacki won career title No. 21 but showed a net loss of 190 rankings points.
That allowed Angelique Kerber to move into the No. 9 spot in the rankings and forced Wozniacki to 10th.
There will likely be at least one change in the Top 10 after this week's WTA Championships. Agnieszka Radwanska has pulled within one point of third-ranked Maria Sharapova for third in the rankings. Sharapova is injured and won't be protecting the 1,050 points she won as a finalist in last year's Championships.
In addition to Wozniacki's win last week, Simona Halep collected her fifth WTA title of 2013 -- second most only to world No. 1 Serena Williams with 10 -- and moves from 18th to No. 14, which is her career high in the rankings.
Williams leads the Red Group in the WTA Championships, which begin with round-robin play Tuesday. Radwanska is in the same group as Williams, along with Kvitova and Kerber. No. 2-ranked Victoria Azarenka is seeded first in the White Group, with Li Na, Errani and Jelena Jankovic completing the field.
The WTA Top 10 listing player's name, home country and rankings points:
1. Serena Williams, United States, 12,040
2. Victoria Azarenka, Belarus, 7,676
3. Maria Sharapova, Russia, 5,891
4. Agnieszka Radwanska, Poland, 5,890
5. 5 Li Na, China, 5,120
6. Petra Kvitova, Czech Republic, 4,370
7. Sara Errani, Italy, 4,190
8. Jelena Jankovic, Serbia, 3,860
9. Angelique Kerber, Germany, 3,715
10. Caroline Wozniacki, Denmark, 3,520