WASHINGTON, March 28 (Xinhua) -- Fourth seed Andy Roddick ended the surprise run of German qualifier Simon Greul with a 6-3, 3-6, 6-2 victory on Tuesday to reach the quarter-finals of the Nasdaq-100 Open in Miami.
The 24-year-old Greul made Roddick work hard for his win, the American advancing on his third match point after a contest lasting one hour 33 minutes.
Ranked 130th in the world, Greul went into the match having previously knocked out Paradorn Srichaphan, Dominik Hrbaty and Tim Henman.
Top seed Roger Federer needed only 58 minutes to eliminate unseeded Dmitry Tursunov 6-3, 6-3. Federer extended his record winning streak of 20 consecutive matches in Masters Series events, and he improved to 25-1 this year.
Also reaching the quarterfinals were big-serving Croats Ivan Ljubicic and Mario Ancic, and unseeded Argentine Agustin Calleri.
12th seed Svetlana Kuznetsova became the first women's semifinalist after edging 21st seed Ai Sugiyama of Japan 6-0, 7-6 (7-4). Enditem
