Wozniacki has reached top spot without winning a Grand Slam
Denmark's Caroline Wozniacki is set to become the new world number one after beating Petra Kvitova to reach the quarter-finals of the China Open.
Wozniacki defeated Kvitova 6-3 6-2 and will overtake Serena Williams when the new rankings are released on Monday.
Wozniacki said: "This is a real big step for me. To be world number one has always been a dream for me."
The 20-year-old is the 20th woman to top the rankings since their inception in 1975.
However, the Dane 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.
Wozniacki said capturing a major title was her next target. "That would be like a dream come true," she added.
Williams, who has held top spot for a total of 123 weeks over the course of her career, has not played since winning her 13th Grand Slam title at Wimbledon in July.
The 29-year-old could make her comeback next week at the WTA tournament in Linz, organisers revealed on Thursday.
"Her flight is booked, her arrival in Linz is scheduled for Sunday morning," said the tournament website.
A comeback at the modest, $220,000 (£193,000) tournament would allow Williams to get herself in condition for the season-ending WTA Championships in Doha at the end of October.
In other matches, second seed Vera Zvonareva dropped the first set against fellow Russian Maria Kirilenko but battled back for a 5-7 6-4 6-2 win.
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.