STUTTGART, Germany — Fabio Fognini opened the defense of his Mercedes Cup title by defeating Andrey Golubev 6-4, 6-4 to advance to the quarterfinals Thursday. The top-seeded Italian will next face the seventh-seeded Santiago Giraldo of Colombia, who defeated qualifier Philipp Davydenko of Russia 6-1, 6-7 (5), 6-3. No. 2 seed Mikhail Youzhny eased past Argentina's Leonardo Mayer 6-1, 6-1. The Russian next plays the eighth-seeded Argentine Federico Delbonis, who defeated Germany's Benjamin Becker 6-7 (6), 6-4, 6-4. The third-seeded Roberto Bautista Agut of Spain beat Louk Sorensen of Ireland 6-3, 1-6, 6-1, for a quarterfinal against compatriot Guillermo Garcia-Lopez. The No. 6 seed earlier defeated Swiss qualifier Yann Marti 7-6 (13), 7-5. Another Spaniard, the fourth-seeded Feliciano Lopez, defeated countryman Daniel Gimeno-Traver 6-7 (3), 6-2, 6-3 and will play Lukas Rosol of the Czech Republic in the last eight. Home favorite Philipp Kohlschreiber won't be there. The German defeated compatriot Jan-Lennard Struff 6-4, 6-3 in their rain-postponed first-round match, but later lost 7-5, 7-6 (5) to Rosol in the second round. Errani, Scheepers thru In Austria, Sara Errani of Italy reached her eighth quarterfinal of the season and first since the French Open by defeating Paula Ormaechea of Argentina 6-3, 6-0 in the second round of the Gastein Ladies Thursday. Errani next plays Chanelle Scheepers of South Africa, who rallied to beat defending champion Yvonne Meusburger 4-6, 6-1, 6-2. Earlier, Shelby Rogers of the US routed the 16th-ranked Carla Suarez Navarro 6-4, 6-0 to reach her first career WTA quarterfinal. Rogers next plays No. 7 Camila Giorgi of Italy, who defeated Austrian wild card Lisa-Maria Moser 6-0, 6-2. Serena out of Bastad World No. 1 Serena Williams has pulled out of next week's Swedish Open after failing to recover from the illness which dramatically ended her Wimbledon campaign. The 32-year-old American star, who was the defending champion at the Bastad claycourt event, withdrew from the Wimbledon doubles event after suffering from what the WTA described as a “viral illness.” Isner, Mahut in last 8 In Newport, two-time champion John Isner and defending champ Nicolas Mahut eased into the quarterfinals at the ATP Tour's Hall of Fame Tennis Championships Wednesday. The top-seeded Isner hammered 11 aces in breezing past qualifier Austin Krajicek 6-3, 6-3 in just 63 minutes in Newport. Isner will face fellow American Jack Sock in a quarterfinal Friday. Former world No. 1 Lleyton Hewitt humbled Croatian qualifier Ante Pavic 6-2, 6-2, while the fourth-seeded Frenchman Mahut rolled over Australia's Luke Saville 6-4, 6-2. Hewitt next faces American Steve Johnson Friday, while Mahut will play hard-serving Australian Samuel Groth. Second-seeded Croat Ivo Karlovic advanced by beating Ukrainian Sergiy Stakhovsky 7-5, 7-6 (7-3). Karlovic fired 18 aces to set up a date with Israeli Dudi Sela. Groth outlasted Tunisian Malek Jaziri 7-6 (9-7), 7-6 (7-3). — Agencies