Spain surged to a 2-0 lead over China in their Fed Cup semi-final, helped by Carla Suarez-Navarro's surprise victory over her much higher ranked opponent.

China, bidding to reach their first Fed Cup final, stumbled in the first singles rubber when world number 68 Peng Shuai was outplayed by 132-ranked Suarez-Navarro 6-3 7-6 at the Beijing International Tennis Centre.

The Spaniard's powerful backhand and speed forced Peng into a series of errors that she could not make up for.

"I was in a mess on the court," Peng said. "I always made mistakes at the key points I ought to win."

The 19-year-old Suarez-Navarro showed her calmness before some 2,000 Beijing spectators, who were enthusiastically cheering for the hosts.

"I felt a little bit nervous in front of such crazy crowds, but later I concentrated and played more and more confidently," she said.

China's misery continued in the second singles rubber when top-ranked Spaniard Nuria Llagostera Vives scored a 6-3 6-4 victory over twice grand slam doubles champion Zheng Jie, who had recently come back after ankle surgery.

World number 76 Llagostera Vives successfully suppressed Zheng's attempt to fight back in the second set, winning a fifth game of 10 deuces. Despite securing the good lead, she warned against celebrating too early.

"We are leading 2-0, but the game isn't over. There are still three matches left so we still need to keep concentrated," Llagostera Vives said.

Spain captain Miguel Margets Lobato admitted he was surprised by the two wins.

"I'm happy with the result," he said. "We expected a 1-1 draw for the first day, but the girls did so well."

Spain need victory in just one of the three remaining rubbers being played on Sunday to book a place in the final.

China would need to win both reverse singles and the doubles to progress, which Zheng said was not an impossible task.

"I believe if we can hold on to the fifth match, we will have great chance to win," she said.

"We certainly have the faith ... in tennis nobody knows the result before the end."

In the weekend's other semi-final, holders Russia were playing the United States in Moscow.

Reuters