Serena saw off Francesca Schiavone of Italy 6-3, 6-4, and then watched older sibling Venus win 6-3, 6-3 for for an eighth victory in as many games against Daniela Hantucheva of Slovakia.

Sunday's fourth round encounter will be the second time the pair have met this year, with Venus winning in straight sets in Miami in March.

Prior to that, Serena had won six in a row including the 2003 final at Wimbledon the last time they met in a Grand Slam tournament.

They have twice met in the US Open final in 2001 when Venus won and the following year when Serena won, but only in the first of their 14 official WTA meetings, at the Australian Open in 1998, have they met earlier than the quarterfinals.

Wimbledon champion Venus said of the clash with her Australian Open champion sister: "There's going to be a lot of hard hitting, a lot of hard serving. We'll both have a few tricks up our sleeves."

On another day of the top players dominating their opponents in the women's draw, No 1 seed Maria Sharapova and tournament favourite Kim Clijsters also scored comfortable straight sets victories.

Sharapova cuffed unseeded German Julia Schruff 6-2, 6-4 and has lost just nine games in three rounds as she campaigns for her second Grand Slam title after last year's unexpected Wimbledon triumph.

She next takes on Sania Mirza after the Indian starlet had balanced 45 winners against 49 unforced errors in defeating France's Marion Bartoli 7-6, 6-4.

The Russian will start a huge favourite in the first meeting between the two 18-year-olds, but she said she would be taking her threat seriously.

"It's going to be another tough one," she said.

"I haven't really seen much of how she plays. I heard she's got a big and powerful game. You just have to go out there and see how it goes."

Clisters, who won three out of the four buildup tournaments ahead of New York, breezed past Japanese veteran Ai Sugiyama 6-1, 6-4 and into a fourth round tie against unseeded Venezuelan Maria Vento-Kabchi.

In the men's tournament, defending champion Roger Federer came through a tougher-than-expected test beating wily Frenchman Fabrice Santoro 7-5, 7-5, 7-6 to reach the third round.

Santoro had Federer rattled and irritable at times with a dazzling array of shot-making, but the Swiss found his best tennis when it mattered to advance to a meeting with Olivier Rochus, the 27th seed from Belgium.

"I had a blast out there today," Federer said. "Rarely the crowd gets into a match like they did tonight. The way he plays, the way I play, I knew it could be a great one."

Third seed Lleyton Hewitt set up a third round meeting with big-hitting American Taylor Dent, but he needed to dig deep at times to see off an unexpectedly stern challenge from Jose Acasuso.

The Argentine, trying to adapt his claycourt game to the demands of hardcourt tennis, took the third seeded Australian to tie-breakers in the opening two sets, but lost both of them to fall 7-6, 7-6, 6-2.

Mirza apart, there was Asian success in the men's tournament, too, as Thailand's Paradorn Srichaphan showed a welcome return to form by defeating French Open semifinalist and sixth seed Nikolay Davydenko of Russia 6-4, 7-5, 6-3.

Paradorn will next take on the second oldest-man in the tournament, 33-year-old Davide Sanguinetti of Itay who defeated out-of-form Spaniard Carlos Moya 3-6, 6-1, 6-2, 6-4.

Comeback of the day went to Germany's Nicolas Kiefer who lost the first two sets to Radek Stepanek of the Czech Republic before clawing his way back to win 4-6, 4-6, 6-4, 6-3, 6-3.

But there was no such end of the rainbow stuff for the new blue-eyed boy of British tennis Andy Murray whose batteries ran dry after levelling at two sets all against Arnaud Clement.