ISTANBUL, Turkey -- Top-ranked Serena Williams advanced to the semifinals of the WTA Championships by sweeping past Petra Kvitova 6-2, 6-3 on Thursday. Williams, the defending champion, won all three matches in her group without dropping a set. Shes bidding for her fourth title in the elite, eight-women tournament. Earlier, Li Na outlasted Jelena Jankovic 6-3, 2-6, 6-3 for her second victory in two matches and eight-seeded Angelique Kerber upset No. 3 Agnieszka Radwanska 6-2, 6-2 to remain in contention for the semifinals. Radwanska was eliminated. Kerber went 0-3 last year in the tournament and this was her first win in the event. She will play Kvitova on Friday for a slot in the last four. Williams needed to win only a set to qualify and she breezed through the first despite fighting off three break points in the very first game. She quickly warmed up to overwhelm the fifth-seeded Kvitova, who won Wimbledon and the WTA title in 2011. Kvitova had to withdraw last year because of injury. "Something told me to hold serve in that game, and Im glad I did," Williams said. "Could have definitely changed things. I could still be out there. I really just dug deep and tried to hold. "When I play top players or a Grand Slam winner, such as Kvitova who has such a dangerous game, youve got to go in there knowing that anything can happen, and I have to be really focused." Williams did not stop after the first set and broke serve again for a decisive 3-1 lead in the second. Williams set up a match point with a service winner and won when Kvitovas return sailed into the net. She finished with 11 aces. "I think her serve is really big, so I knew I wanted to hold. I served well," said Williams, who has never lost to Kvitova in five matches. Williams, 32, is enjoying the finest season in her career, having already won 10 titles. She added the French Open and U.S. Open titles to bring her Grand Slam record to 17 championships and is 76-4 for the year. Making her eighth appearance in the event, Williams is looking to become the first player to successfully defend the title since Justine Henin in 2007. Henin was also the last to win 10 titles in a season, in 2007. Williams has clinched the year-end No. 1 ranking for the third time in her career after 2002 and 2009. The key to Lis victory in an error-filled match full of long rallies was her break of serve in the third set for a 4-3 lead. She never looked behind again, winning the last three games. Jankovic hit a backhand into the net on Lis second match point. The fourth-seeded Li has a 2-0 record in the White Group and looks likely to advance to the semifinals for the first time. Seventh-seeded Jankovic is 1-1. Jankovic is back in the tournament for the first time in three years. The two of them and Victoria Azarenka are vying to make the semis. "It was tight, yeah, but at least its better than the last two years," said Li, who won only once in 2011 and 2012. She was pleased to add she had one foot in the semis but her other foot was "still out of the door." Kerber is 1-1 in the Red Group. Radwanska fell to 0-3. "Im feeling good," Kerber said. "I was really playing very well today ... I was focused from the first point." Li holds a 6-4 career edge over her Serbian friend, but she had to work hard for her win. Both players were inconsistent and error-prone. Li had 45 unforced errors and 21 winners, Jankovic 36 unforced errors and 17 winners. "We had a great fight," Jankovic said. "In the third set it was just a couple of points. I got broken in that (seventh) game. She lobbed me, and the ball went on the line." Li followed the lob with a crisp backhand winner to take the game. "They were the crucial points at that stage and made a difference," Jankovic said. Tyrone Taylor Brewers Jersey . The Wizards announced Friday that Webster had surgery to repair a herniated disc in his lower back. The operation was performed Thursday in Los Angeles. Teddy Higuera Brewers Jersey . The light-heavyweight champion and number one ranked pound-for-pound fighter in the world is on an 11-fight UFC winning streak, the longest in the history of the weight class. https://www.cheapbrewers.com/1209y-christian-yelich-jersey-brewers.html .com) - Jeff Teague finished with a game-high 26 points and eight assists as the Atlanta Hawks held off the Utah Jazz, 98-92, on Friday. Fake Brewers Jerseys .Y. - Matt Harvey wants to make sure hes on the mound in late October — if the New York Mets get there for the first time since 2006. Travis Shaw Brewers Jersey . Adrian Wojnarowski of Yahoo! Sports reports that the Raptors have traded forward Steve Novak along with a second-round pick to the Utah Jazz in exchange for guard Diante Garrett - who will then be waived.BUCHAREST, Romania -- Sixth-seeded Andreas Seppi was knocked out of the first round of the Nastase Tiriac Trophy on Tuesday, along with seventh-seeded Nicolas Mahut. Carlos Berlocq of Argentina ousted Italys Seppi 6-0, 2-6, 7-6 (4) on the outdoor clay at the BNR Arenas, while qualifier Paul-Henri Mathieu defeated Mahut 6-3, 6-1 in all-French contest. Defending champion Lukas Rosol made a winning start, beating Italian Filippo Volandri 6-1, 7-6 (6).dddddddddddd Romanian hope Victor Hanescu defeated Israels Dudi Sela, 6-3, 6-4 and wild card entrant Marius Copil of Romania downed Frenchman Adrian Mannarino 6-1, 6-4 in a match lasting just over one hour. In other matches, Denis Istomin of Uzbekistan ousted Brazils Thomaz Bellucci 7-6 (6), 7-6 (6) and Robin Haase of the Netherlands beat Australias Matthew Ebden 6-4, 6-3. ' ' '