Top seed Andy Roddick defeated unseeded Frenchman Arnaud Clement for the first time on Wednesday to advance to the quarter-finals of the Kroger St Jude championships in Memphis, Tennessee.
Seeking a second consecutive ATP title after taking the San Jose Open last weekend, the American world number three won 6-3, 6-3 in the second-round match, claiming a maiden victory over Clement after two previous defeats.
Roddick's victory sets up a last eight encounter against the winner of Thursday's match between compatriots Mardy Fish and Robby Ginepri.
Third seeded Tommy Haas of Germany maintained his good form and broke serve three times en route to a 6-4, 6-4 first-round victory over American
Haas reached the semi-finals in San Jose before losing in straight sets to Roddick.
In the WTA event, top seed and defending champion Vera Zvonareva of Russia beat France's Severine Beltrame 7-6, 6-3 and third-seeded American Meghann Shaughnessy defeated Hana Sromova of the Czech Republic 6-3, 6-2 in second-round matches.
Promising seventh seed Nicole Vaidisova looked strong in her 6-2, 6-2 second-round win over Puerto Rican Kristina Brandi.
In the quarter-finals, the 15-year-old Czech will play unseeded American Jamea Jackson, who upset second seeded Amy Frazier in the first round and Bulgaria's Sesil Karatantcheva on Tuesday.