Former world number one Lleyton Hewitt moved into the last eight of the US Open with a comprehensive victory against Slovakia's Karol Beck.
Hewitt was made to work in the first set, which he eventually took 6-4.
Once he fell behind Beck appeared to lose heart and he put up little resistance in the final two sets, losing them 6-2 6-2.
Hewitt will now play in-form German Tommy Haas for a place in the last four after he beat Czech Tomas Berdych.
The 23-year-old is in fearsome form at Flushing Meadows, where he has yet to drop a set on his way to extending his match-winning streak to 14.
Hewitt, who won the title in 2001, wrapped up his victory over Beck in one hour, 40 minutes.
"He played some good tennis in the first set but I managed
to step it up at 4-4 to break his serve, after that he went away
a little bit," said the Australian.
"I am happy I am getting through in straight sets rather than playing four or five.
"But I am going to have to step it up on the big points from here on."
Beck was disappointed with his performance against his combative opponent.
"It was easy to beat me today, he only had to play average," the 22-year-old lamented.
Germany's Tommy Haas ended 18-year-old Berdych's run at the US Open with a competent 7-6 6-1 7-5 victory.
The first set was evenly-matched as neither player was able to carve out a break.
The same theme continued in the tie-break but it was Haas who made the least errors to edge it 8-6.
The 26-year-old then stamped his authority on the match, racing to the second set as Berdych lost his way.
The Czech fought bravely in his best-ever Grand Slam showing but could not stop Haas breaking him in the third.
"I was like sinking on the court," said the teenager. "But I think the result in this tournament is very good for me."
The German has found his form again after recovering from a long-term shoulder injury which left him sidelined for the entire 2003 season.
"I am playing some great tennis," said Haas.
"I was lucky to come from 6-3 down in the tiebreak and then played well."