Former champions Rafael Nadal and Agnieszka Radwanska both moved into quarterfinals at the China Open on Wednesday.
Nadal, the 2005 champion here in Beijing, was made to work before beating Vasek Pospisil of Canada 7-6(3), 6-4 while 2011 champion Radwanska won her third round match easily after 14th seed Madison Keys of the United States retired citing an injury.
Both Nadal and Pospisil held serve in the opening set before the match was forced into a tiebreak. The Spaniard was much better on big points and won the tiebreak at 7-3.
In the second set, Nadal looked more convincing and broke once to win at 6-4.
The major upset in men's singles came from world number five and second seed Tomas Berdych of the Czech Republic, who crashed out at the first hurdle falling 6-4, 6-4 to Uruguay's Pablo Cuevas.
Berdych, also a former winner in Beijing, was returning to the Chinese capital having won his first ATP World Tour title of the year in Shenzhen on Monday. Against World No. 37 Cuevas, however, he was unable to back it up.
"It's always a difficult part of the year. We have to travel a lot. The conditions are always very different, very difficult, week by week here in China. It's not easy to adjust," Berdych said.
There were no such troubles for Spanish veteran David Ferrer who defeated Lukas Rosol of the Czech Republic 7-6(5), 6-2 to progress to the quarterfinals.
Next up for the 33 years old is Chinese Taipei's Lu Yen-Hsun, who continued to make the most of his wildcard to upset Milos Raonic's conqueror Viktor Troicki 6-4, 7-5.
There was also round of 16 win for American Jack Sock, who scored a 6-3, 6-1 win over Austrian Andreas Haider-Maurer.
In women's part, Germany's 10th seed Angelique Kerber made short work of 8th seed Caroline Wozniacki of Denmark 6-2, 6-3 to join Radwanska in the last eight.
Timea Bacsinszky of Switzerland and Italy's Sara Errani also made quarterfinals.
In a second round match, rising star Garbine Muguruza of Spain blitzed Irina Falconi of the United States 6-1, 6-1.
