Belgian second seed Kim Clijsters had few problems as she wrapped up another comfortable victory inside an hour against unseeded Russian Dinara Safina.
Clijsters beat Safina - sister of male star Marat - 6-2 6-1 in 57 minutes.
Safina could not repeat the form that saw her beat 27th seed Amanda Coetzer and Clijsters secured the win when the Russian sent a forehand return long.
That result means that the 20-year-old Belgian has dropped just eight games in reaching the last 16.
Clijsters' hopes of clinching her first Grand Slam title were boosted further when Venus Williams was knocked out by Lisa Raymond.
The Belgian was seeded to meet Williams in the semi-finals, but the second seed vowed to take nothing for granted.
"I'm not looking too far ahead. I know my next round will be tough. That's what I'm focusing on," she said.
Clijsters also said she has been trying deliberately to finish off opponents quickly because she is still concerned about a recent ankle injury.
"That's something I want to stay focused on...to make sure I don't get players coming back into a match."