Li Na of China returns a shot against Sabine Lisicki of Germany during their match at the China Open tennis tournament in Beijing October 2, 2013.[Photo/Agencies]

Nadal, the world number two, dropped two serves but broke back three times in the opening set to take it at 6-4.

In the second set, both players held serve well until the match was dragged into tiebreak. The gritty Spaniard pulled off some convincing groundstrokes to nail down the tiebreak and the whole match at 7-3.

The second round on women's part were all wrapped up on Wednesday, with Polona Hercog of Slovenia dismissing Serb Ana Ivanovic in straight sets -- it was her third career win over a top 15 player.

"It was a big challenge for me to go out there on a big court and play against Ana Ivanovic, and I'm just really happy the way it turned out," Hercog said. "It's probably one of the biggest victories for me. I beat Bartoli before when she was top 10, but Ana is on her way back so it's a very big win for me."

Elsewhere, No.8 seed Jelena Jankovic of Serbia looked headed for a straightforward win as she led 6-3, 3-1 but had to grind out a 6-3, 5-7, 6-3 win in two and a half hours against Kazakhstani qualifier Galina Voskoboeva.

No.3 seed Agnieszka Radwanska of Poland cruised past American Madison Keys in an hour and 15 minutes 6-3, 6-2.

"I played her at Wimbledon a few months ago, so I kind of knew what to expect, especially the big serve," Radwanska said. "We played a really long three-set match there. She was really serving unbelievable. So I knew I had to stand two steps backwards to reach that serve. But I don't think her percentage of first serves was as good as the matches before - it was a little bit easier for me today."

"But she's one of the youngest talented players coming out. Last year I was asked me to name which of the players can be the most dangerous to the top seeds, and I actually said it's Madison Keys, because she can play very good tennis. In a couple of years we're going to see her more often."

Earlier, Andrea Petkovic of Germany followed up her first round upset over Victoria Azarenka with a 4-6, 6-4, 6-1 win over two-time China Open winner Svetlana Kuznetsova.