SHANGHAI — Roger Federer assured himself the No. 1 ranking for the 300th week of his career by beating Davis Cup teammate Stanislas Wawrinka 4-6, 7-6 (4), 6-0 Thursday in the third round of the Shanghai Masters.
The Swiss star will play 10th-seeded Marin Cilic in the quarterfinals after the Croat beat Fernando Verdasco of Spain 4-6, 6-1, 6-4. Novak Djokovic and Andy Murray also reached the quarterfinals. Djokovic defeated Feliciano Lopez of Spain 6-3, 6-3, and Murray beat Alexandr Dolgopolov of Ukraine 6-2, 6-2.
Murray will play unseeded Radek Stepanek of the Czech Republic. Stepanek upset eighth-seeded John Isner 6-4, 6-7 (5), 6-3.
Federer struggled with his backhand for much of the first two sets before recovering.
"I just keep on trying," he said. "I knew I had a chance going into the breaker and I was just a little lucky. But I never stopped believing. But he was the better player for two sets. It was great finding a way out."
The second-seeded Djokovic had 12 aces and won 27 of 29 first-serve points. The third game of the second set was the only time in the match that the Serb lost two points on serve.
Djokovic will play Tommy Haas of Germany, who defeated Djokovic's countryman, Janko Tipsarevic, 6-2, 6-1. Fourth-seeded Tomas Berdych of the Czech Republic defeated Sam Querrey of the United States 6-2, 6-7 (3), 6-4, and fifth-seeded Jo-Wilfried Tsonga beat Marcos Baghdatis of Cyprus 6-2, 7-6 (2).
Berdych will play fifth-seeded Jo-Wilfried Tsonga. The Frenchman downed Marcos Baghdatis of Cyprus 6-2, 7-6 (2).
At Osaka, Japan, unseeded Pauline Parmentier of France reached the quarterfinals of the Japan Open by beating second-seeded Zheng Jie of China 6-3, 6-4.
Parmentier won 74 percent of her first serves in the match and will next face Heather Watson of Britain. Watson beat sixth-seeded Anabel Medina Garrigues of Spain 6-7 (4), 6-2, 6-3.
Also, seventh-seeded Chanelle Scheepers of South Africa defeated Mirjana Lucic of Croatia 6-2, 6-2 and will next meet Misaki Doi of Japan. Eighth-seeded Laura Robson of Britain also advanced to the quarterfinals, beating Chinese qualifier Yi-Miao Zhou 6-4, 6-4. Robson will next play Kai-Chen Chang of Taiwan.
At Linz, Austria, top-ranked Victoria Azarenka and two-time former champion Ana Ivanovic won in straight sets to reach the quarterfinals of the Generali Ladies.
Azarenka beat Simona Halep of Romania 6-1, 6-1, and Ivanovic defeated Andrea Petkovic of Germany 6-4, 6-3.
Azarenka dominated play from the baseline and hit 20 winners.
Azarenka, who has dropped only four games in two matches, will next play Petra Martic after the Croat defeated Patricia Mayr-Achleitner of Austria 6-2, 3-6, 6-0. Martic hit seven aces to reach her 10th career quarterfinal. Mayr-Achleitner won just five of 29 points in the deciding set.
The second-seeded Ivanovic had to dig deep against Petkovic, who has dropped to 192nd because of an injured right ankle. The German had been down an early break in the second set but rallied to make it 3-3 before losing.
Ivanovic, the 2008 and 2010 champion who has at least reached the quarterfinals all five times at the event, will take on Kirsten Flipkens. The Belgian defeated Mallory Burdette of the United States 4-6, 6-1, 7-5.
Burdette twice came back from a break down in the decider but missed two break-point chances at 6-5 to force a tiebreaker.
Bethanie Mattek-Sands reached her first quarterfinal of the season by defeating Carla Suarez Navarro of Spain 6-3, 6-3.
The 201st-ranked American is climbing back up the rankings after recent hip, back and left foot injuries. She will face next face Irina-Camelia Begu of Romania. Begu, who lost in qualifying but replaced Anna Tatishvili of Georgia in the main draw, beat Kiki Bertens of the Netherlands 6-4, 7-6 (7).