Both players have had superlative years on the tour.
Djokovic, atop the rankings for the last 48 weeks and 101 weeks overall, opens defense of his China Open with a 52-9 record, including his three-peat of the Australian Open and two other titles this year.
Nadal, coming off a knee injury that caused him to miss the second half of 2012 and the 2013 Australian Open, is 61-3 with 10 titles, including the French Open and the U.S. Open. He's also 3-1 versus Djokovic this year.
That has allowed Nadal to pile up rankings points, putting him on the verge of returning to the No. 1 spot. . Djokovic needs to win the China Open and have Nadal not reach the final to keep the No. 1 ranking.
Djokovic's 101 weeks as No. 1 is one fewer than Nadal's 102-week career tenure.
It's been 506 weeks since the No. 1-ranked ATP player wasn't named Roger Federer, Djokovic or Nadal. Federer owns the record with 302 weeks atop the rankings. Nadal is seventh on the all-time list, with Djokovic tied with Andre Agassi for eighth.
Berdych was the runner-up to No. 11 Milos Raonic at the Thailand Open. Wawrinka dropped a semifinal match to Julien Benneteau at the Malaysian Open.
Benneteau fell to 0-9 in ATP finals, losing to first-time champion Joao Sousa. Sousa jumps 26 places to a career-high 51st in the rankings after the win. Benneteau inches up one spot to 32nd.
There are four other Top 10 players in addition to Djokovic and Nadal at the China Open while Juan Martin del Porto and Jo-Wilfried Tsonga top the field this week at the Japan Open.
The ATP Top 10, listing player's name, home country and ranking points:
1. Novak Djokovic, Serbia, 11,120
2. Rafael Nadal, Spain, 10,860
3. Andy Murray, Great Britain, 7,075
4. David Ferrer, Spain, 6,710
5. Tomas Berdych, Czech Republic, 4,520
6. Roger Federer, Switzerland, 4,515
7. Juan Martin del Potro, 4,425
8. Jo-Wilfried Tsonga, France, 3,325
9. Stanislas Wawrinka, Switzerland, 3,150
10. Richard Gasquet, France, 3,005