Djokovic, Radwanska reach China Open quarterfinals
Djokovic rushed through the first set then lost his serve twice in the second before winning the second-round match.
Florian Mayer of Germany also made the last eight.
Radwanska, coming off a loss in the final of the Japan Open on Sunday, struggled in her first matchup against the Spaniard. Radwanska broke six times and lost her own serve seven times.
Jankovic fell apart after leading 5-2, going out to Carla Suarez Navarro of Spain 7-5, 6-4.
"Jelena is always difficult to play, but I played well," Suarez Navarro said. "She always fights a lot, and I'm happy to have finished it off."
Copyright 2012 by The Associated Press
This story is from ESPN.com's automated news wire. Wire index
MORE TENNIS HEADLINES
- Serena extends streak, reaches Italian final
- Sharapova withdraws prior to quarter in Rome
- US Open tennis exclusively on ESPN in '15
- Murray says he's doubtful for French Open