Lleyton Hewitt, the 2001 champion, routed Feliciano Lopez of Spain 6-1 6-4 6-2 in the third round of the US Open and cannot meet another seed until the semi-finals.
Earlier, second seed and defending champion Andy Roddick cruised into the fourth round with yet another romp, a 6-1 6-3 6-3 destruction of Argentina's Guillermo Canas.
The American's unbelievable serving continued with 21 aces and no double faults.
Roddick is getting used to some fast starts, losing a total of one game in the first set of his first three matches.
He now meets seed 18 Tommy Robredo of Spain, who defeated Austrian qualifier Alexander Peya 6-3 6-3 6-2.
Germany's Tommy Haas defeated Brazilian qualifier Ricardo Mello 6-2 6-3 7-5 to advance to the fourth round.
Haas, who missed last year's US Open to recover from surgery on his right shoulder, needed five sets to beat Italian Davide Sanguinetti in the first round and four to eliminate Sebastien Grosjean of France in the second round.
The 26-year-old Haas reached the fourth round here for the fourth time but he has never advanced to the quarter-finals at the National Tennis Center.
Other winners included Joachim Johansson of Sweden and unseeded Michael Llodra of France, Tomas Berdych of the Czech Republic and Slovakia's Karol Beck.
Amelie Mauresmo powered into the quarter-finals with a 6-4 6-2 victory over Francesca Schiavone of Italy.
The second seed now meets sixth seed Elena Dementieva, who rallied for a 1-6 6-4 6-3 victory over fellow Russian Vera Zvonareva.
America's Serena Williams also won her fourth-round match, beating Patty Schnyder of Switzerland 6-4 6-2.
Third seed Williams, again wearing a controversial black outfit, was too powerful for the Swiss player who was seeded 15.
In the quarter-finals, Williams will again renew her rivalry with fellow countrywoman Jennifer Capriati, who weathered a rough patch before beating Ai Sugiyama of Japan 7-5 6-2.
Williams and Capriati will meet for the third straight time in a Grand Slam event.
Capriati won in three sets in the quarter-finals of the French Open and Williams responded with a straight-sets last-eight triumph at Wimbledon.
Filed by Barry McEneaney
