Djokovic escaped Fernando Verdasco 7-5, 2-6, 6-2. Verdasco cashed in both of his break chances in the second set but only managed one break opportunity in the third, which Djokovic saved, and his upset bid fell short.
Djokovic had a pair of third-set breaks to advance to the tournament quarterfinals. He must repeat as the China Open champion -- he also won the event in 2009 and '10 -- and have Rafale Nadal lose in the quarterfinals or semifinals to keep the No. 1 ranking.
Djokovic next takes on Sam Querrey, who ousted sixth-seeded Stanislas Wawrinka 6-3, 7-6 (7-2). Querrey pounded out 11 aces and won 72 percent of the points on serve in beating Wawrinka for the first time in four career meetings.
Third-seeded David Ferrer overcame an inconsistent first set for a 5-7, 6-1, 6-2 decision over Marinko Matosevic. Ferrer suffered three breaks in the first set but faced only one other break point the rest of the way.
Richard Gasquet, the No. 5 seed, moved into the quarterfinals by taking out Bernard Tomic 7-6 (7-2), 6-4. Gasquet had 15 break-point opportunities, converting three of them.
Djokovic goes against Querrey and Ferrer plays Gasquet in Friday's quarterfinals. The other half of the draw has Nadal going against Fabio Fognini while fourth-seeded Tomas Berdych takes on No. 8 John Isner.