World number one men's tennis player Roger Federer of Switzerland and Australian Open champion Marat Safin of Russia highlight play Friday at the Cincinnati Masters tennis tournament in Ohio.

Federer, the top seed, takes on Jose Acasuso of Argentina in a quarterfinal match. Safin plays American Robby Ginepri for a spot in the semifinals.

Last year's runner up, Lleyton Hewitt of Australia has a quarterfinal match against Russian Nikolay Davydenko, while fifth seeded Andy Roddick of the United States takes on another Russian, Mikhail Youzhny, for a place in the final four.

The hard-court tournament is a key warm-up for the U.S. Open, the last major tournament of the year, which starts August 29 in New York.

Some information for this report provided by AFP and AP.