Wozniacki has reached top spot without winning a Grand Slam
Denmark's Caroline Wozniacki is the new women's world number one after beating Petra Kvitova to reach the quarter-finals of the China Open in Beijing.
Wozniacki defeated her Czech opponent 6-3 6-2 to overtake Serena Williams at the top of the rankings.
The 20-year-old Wozniacki is the 20th woman to top the rankings since their inception in 1975.
However, Wozniacki is the third player in the last two years to reach the top without winning a Grand Slam title.
Serbia's Jelena Jankovic and Russia's Dinara Safina are still without a major title despite topping the rankings in 2008 and 2009 respectively.
In other matches, Serbia's Ana Ivanovic beat Russian seventh seed Elena Dementieva 7-6 (7-2) 7-6 (7-4).
Home favourite Li Na, the ninth seed, trounced Germany's Angelique Kerber 6-2 6-0 in only 48 minutes, while Anastasija Sevastova of Latvia had a walkover against 13th seed Nadia Petrova of Russia.