Top-seeded Nadia Petrova beat Melinda Czink of Hungary 6-1, 6-4 Friday to reach the Bell Challenge semifinals.

Roger Federer pulled out of his quarterfinal match against James Blake because of a back injury Friday, while Rafael Nadal had to retire from his match against Nikolay Davydenko due to leg pain.

Roger Federer has pulled out of his quarterfinal against James Blake at the Paris Masters because of a back injury. Federer said on his Web site that his back was stiff this week and felt worse when he woke up Friday, forcing him to pull out of the match. The 13-time Grand Slam champion has never reached the semifinals at the Bercy indoor arena after losing in the 2002 and 2003 quarterfinals.

Hometown favorite Aleksandra Wozniak beat qualifier Carly Gullickson 6-3, 6-2 Thursday in the second round of the Bell Challenge.

Rafael Nadal and Roger Federer rolled into the Paris Masters quarterfinals without the ousted Novak Djokovic.

Arlen Kantarian resigned as CEO of professional tennis for the U.S. Tennis Association on Thursday after running the U.S. Open since 2000. Kantarian will depart at the end of the year. He is a former NFL and Radio City executive who brought instant replay to Grand Slam tennis, moved the U.S. Open women's final into prime time, and launched the U.S.

Rafael Nadal, Roger Federer and defending champion David Nalbandian reached the third round of the Paris Masters without dropping a set.

Top seed Nadia Petrova breezed past Maria Mokh 6-1, 6-2 on Tuesday in the Bell Challenge.

Juan Martin del Potro beat Mario Ancic 6-0, 6-4 in the second round of the Paris Masters on Tuesday, boosting his chances of reaching the season-ending Masters Cup.

Roger Federer will play for Switzerland in the Davis Cup against the United States next March.