Los Angeles, CA -- (Sports Network) - Top-seeded American Andy Roddick and sixth-seeded American Mardy Fish each secured a berth in the semifinals at the $475,000 Countrywide Classic tennis event.

Roddick had no problems moving into the semis as he easily dispatched France's Marc Gicquel 6-3, 6-1, while Fish handled France's Florent Serra 6-4, 6-4 on the hardcourts at the Los Angeles Tennis Center on Friday.

In other action, German Denis Gremelmayr stunned fifth-seeded Russian Marat Safin, who reached the Wimbledon semis last month, 3-6, 6-3, 6-2.

Meanwhile, Juan Martin Del Potro of Argentina bested American Amer Delic in straight sets, 7-6 (8-6), 6-2.

The red-hot 6-foot-5 Del Potro is riding an impressive 12-match winning streak, which includes back-to-back titles in Stuttgart and Kitzbuhel in his previous two events.

The 2008 Countrywide winner will collect $79,000.