“It was not easy today, and I m happy to win, of course, even if I was supposed to win,” Tsonga said.
In the next round, he will face Juan Carlos Ferrero of Spain, who beat Marcel Granollers 6-4, 6-4.
“I think he s a great player,” Ferrero said of Tsonga. “He s in a good shape. He s been playing very good tennis most of the season on the hard courts, and of course he s one of the favorites to win the tournament.”
Also in Friday s quarterfinals, Tomas Berdych of the Czech Republic will face Fernando Verdasco of Spain, Ivan Ljubicic of Croatia will meet Mikhail Youzhny of Russia, and Kevin Anderson of South Africa will play Marin Cilic of Croatia.
In the women s tournament, Wozniacki rebounded from last week s loss to Kanepi at the Pan Pacific Open in Tokyo.
“I knew it was going to be a tough match,” the top-ranked Dane said. “I m really happy to get this win and get my revenge.”
Wozniacki will next face Flavia Pennetta of Italy, who defeated Dominika Cibulkova of Slovakia 6-1, 4-6, 6-4.
Also, second-seeded Victoria Azarenka pulled out of the tournament because of a right foot injury, giving 13th-seeded Anastasia Pavlyuchenkova of Russia a walkover win.
Azarenka, who lost in doubles on Wednesday, said her foot has been bothering her since Tokyo.
“I m not sure about recovery time but I will consult my doctor,” the fourth-ranked Azarenka said.
In other quarterfinal matches, Pavlyuchenkova will face Andrea Petkovic of Germany and Monica Niculescu of Romania will take on Maria Kirilenko of Russia.