Roger Federer remained on course to complete the Miami-Indian Wells Masters Series double for the second consecutive year on Tuesday with victory over Dmitry Tursunov to reach the Nasdaq-100 Open quarter-finals.
Champion at the Pacific Life Open in Indian Wells earlier this month, the Swiss top seed beat the Russian 6-3, 6-3 to notch up his 45th straight victory on U.S. soil.
"It's always more difficult to play a guy for the first time," Federer told reporters after securing his 25th victory of the season against just one loss.
"I did well today. He's dangerous and I needed to play a solid game. I'm very pleased. I had to make adjustments for a setting sun and the wind out there."
In the women's event, Russian 12th seed Svetlana Kuznetsova became the first player to reach the semi-finals with a 6-0, 7-6 triumph over Ai Sugiyama of Japan.
Earlier, men's fourth seed Andy Roddick ended the surprise run of Simon Greul, beating the German qualifier 6-3, 3-6, 6-2.
INTO GROOVE
Greul, ranked 130th in the world, went into the match having knocked out Paradorn Srichaphan, Dominik Hrbaty and Tim Henman.
The 24-year-old made Roddick work hard for his win, the American advancing on his third match point after a contest lasting one hour 33 minutes.
"I let him get into a groove in the second set," Roddick told reporters. "He started getting confidence and swung from the hip.
"If I'd let it go any further in the third he would have gained a lot of confidence and momentum. He's an awkward player to compete against."
Roddick, the 2004 champion, has yet to reach a final this season.
Croatian Davis Cup team mates Mario Ancic and Ivan Ljubicic progressed with the minimum of fuss.
Ancic, the 22nd seed, upset Russian fifth seed Nikolay Davydenko 7-5, 6-4 while number six Ljubicic swept past Belgian Christophe Rochus 6-3, 6-1.
Ljubicic, who hit 13 aces, next meets unseeded Argentine Agustin Calleri, a 3-6, 6-3, 7-5 winner over 16th seed Nicolas Kiefer of Germany.
