Andrey Golubev of Kazakhstan upset defending champion Nikolay Davydenko of Russia 6-4, 6-4 to reach the quarterfinals of the German Open on Thursday. Third-seeded Juergen Melzer of Austria advanced to the last eight by beating Jeremy Chardy of France 7-5, 7-6 (4). Sixth-seeded Juan Carlos Ferrero of Spain beat Jarkko Nieminen of Finland 6-2, 3-6, 6-4 to reach the quarterfinals. Seventh-seeded Thomaz Bellucci of Brazil defeated No. 10 Philipp Kohlschreiber of Germany 7-5, 6-4, while Denis Istomin of Uzbekistan beat wild card Julian Reister of Germany 3-6, 6-3, 7-6 (3). Florian Mayer of Germany made the last eight by dispatching Maximo Gonzalez of Argentina 7-6 (1), 6-0. In other matches, Andreas Seppi edged Fabio Fognini 6-4, 6-4 in an all-Italian encounter and another Italian, Potito Starace, advanced by rallying to beat Spanish qualifier Pere Riba 4-6, 6-4, 6-4. Jankovic retires injured Second-ranked Jelena Jankovic injured her ankle during the second round of the Slovenia Open and retired hurt Thursday. Jankovic cruised through a 6-1 first set against Belarus qualifier Anastasiya Yakimova then stepped awkwardly early in the second. Jankovic lost that set 6-3 and eventually retired after losing the first game of the third. It was Jankovic's first tournament since Wimbledon, where she retired in the fourth round with a back injury. Yakimova will next face Ksenia Pervak, who beat qualifier Alexandra Panova 6-2, 7-5 in an all-Russian match. Third-seeded Anastasia Pavlyuchenkova of Russia beat Rossana De Los Rios of Paraguay 6-3, 6-0 to face Johanna Larsson of Sweden, who reached her first WTA quarterfinals by defeating Maria Elena Camerin of Italy 7-5, 6-1. Cornet stuns Petkovic Alize Cornet of France has beaten defending champion and top-seeded Andrea Petkovic of Germany 6-2, 7-5 to reach the quarterfinals of the Gastein Ladies event at Bad Gastein, Austria. Cornet will face Austrian wildcard Patricia Mayr, who upset No. 7-seeded Tathiana Garbin of Italy 6-3, 6-4. Julia Goerges of Germany also advanced by defeating Mariya Koryttseva of Ukraine 6-2, 7-5. Isner prevails No. 2 seed John Isner fought through another final-set tiebreaker with a 4-6, 7-6 (6), 7-6 (7) victory over Gilles Muller of Luxembourg in the second round of the Atlanta Tennis Championships Wednesday. Isner, who became a household tennis name after winning a three-day, 183-game match at Wimbledon last month, improved to 16-5 in career final-set tiebreakers. The American had not played since he lost in the second round at Wimbledon, the day after his record win over Nicolas Mahut of France. Michael Russell of the US will face Isner in the quarterfinals after defeating German Rainer Schuettler 1-6, 6-2, 7-5. Taylor Dent beat No. 4 seed Horacio Zeballos of Argentina 4-6, 6-2, 6-0 to advance to his first ATP tour quarterfinal since Tokyo in October 2005. The victory was his seventh in 20 matches this year. Dent will face No. 6 seed Mardy Fish, a 6-1, 7-5 winner over fellow
