The fourth-seeded Sharapova saved seven of nine break points she faced in a 6-2, 6-2 second-round win over Elina Svitolina of Ukraine, a semifinalist last week at the Wuhan Open.

"She's sort of an up-and-comer. But playing really well. Has had some big results this year against top players," Sharapova said of Svitolina. "Maybe the scoreline was a bit easier than the match showed."

Djokovic improved to 20-0 at the China Open with a 6-2, 6-1 win over Spain's Guillermo Garcia-Lopez in the first round.

The top-seeded Serb is seeking his fifth title in Beijing, having won the tournament every time he's entered in 2009, 2010, 2012 and 2013. This was his first outing since losing to Kei Nishikori in the semifinals of the U.S. Open.

All of the big men's names were in action on Tuesday, with Rafael Nadal and Andy Murray opening their accounts.

The fifth-seeded Radwanska, meanwhile, became the highest seed to lose in the women's draw, falling to Roberta Vinci of Italy 6-4, 6-4.

Since winning the Canadian Open in August, the Pole hasn't advanced past the quarterfinals in five events. She could have wrapped up her spot in the season-ending WTA Finals this week, but fell in the second round in both Wuhan and now Beijing.

In other matches, second-seeded Simona Halep survived a tight match against 167th-ranked Lin Zhu of China, prevailing 7-5, 6-4. Halep is also seeking to regain her form after crashing out to 121st-ranked Mirjana Lucic-Baroni at the U.S. Open.

No. 1 Serena Williams took on Tsvetana Pironkova of Bulgaria late Tuesday, while her sister Venus met rising French player Caroline Garcia for the second straight week; Garcia won in Wuhan in three sets.