David Nalbandian set up an all-Argentine clash with Guillermo Canas after easing to a straight-sets win over Wayne Ferreira.
The Argentine always looked in control as he strolled to a 6-2 6-4 7-5 victory which means he has still to lose a set in the tournament.
At times he looked to be toying with the South African as he continually played to Ferreira's powerful forehand.
But whenever Ferreira looked to be making inroads into the match, Nalbandian found the shots to pull clear again.
Lleyton Hewitt had a tough encounter with Spanish teenager Rafael Nadal, but came through in straight sets.
Hewitt needed two tie-breakers to put himself in charge but then ran through the third set to clinch victory 7-6 (7-2) 7-6 (7/5) 6-2.
Hewitt will now face second seed Roger Federer after the Wimbledon champion trounced Todd Reid.
In other third-round encounters, Australian 10th seed Mark Philippoussis equalled his best ever run at his home Grand Slam by beating Croatia's Mario Ancic in straight sets.
But the unseeded Croat, ranked 73 in the world, made Philippoussis work hard for every point.
Ancic endeavoured to come into the net to challenge the big-serving Australian with some success, breaking him twice.
However, Philippoussis achieved five breaks and found the right shots on crucial points to win 6-4 7-6 (7/2) 6-2.
Philippoussis will Hicham Arazi after the Moroccan came from a set down to beat 26th seed Albert Costa.
Arazi eventually came through 2-6 7-6 (7/2) 6-2 6-1 to equal his best showing in a Grand Slam.
Andrei Pavel staged a remarkable recovery to beat 14th seed Jiri Novak 4-6 3-6 7-5 7-6 (7/3) 6-4.
Pavel now faces French Open champion Juan Carlos Ferrero of
Spain in the last 16.
Ferrero defeated Swedish giant Joachim
Johansson in a fourth set tie-break to win 6-1 7-6 (7/4) 6-7