Hingis, the top seed, looked dominant for the second straight match as she guns for a fourth Australian Open title in five years. The world No. 1, who needed only 39 minutes to win her first-round match on Tuesday, was on the court for just 40 minutes Thursday as she crushed Els Callens of Belgium, 6-1, 6-0.

Williams, the reigning Wimbledon and U.S. Open champion, bounced back from her three-set struggle in the first round as she defeated fellow American Meghann Shaughnessy, 6-3, 7-6 (7-3), to extend her winning streak on hard courts to 27 matches.

A finalist here the last two years, Kafelnikov was taken to the limit in one of three marquee second-round matches on the men's side. The fifth-seeded Russian took advantage of a weary Nicolas Kiefer and gutted out a 6-2, 3-6, 3-6, 6-3, 6-0 win over the 2000 quarterfinalist from Germany.

Top seed Gustavo Kuerten of Brazil and No. 7 Lleyton Hewitt of Australia also face stiff competition as they try to reach the third round.

Kuerten, who overcame a thigh injury to outduel fellow South American Gaston Gaudio of Argentina in four tight sets Tuesday, faces former top-10 player Greg Rusedski of Britain.

Two days after needing five sets to defeat Sweden's Jonas Bjorkman, sets, Hewitt encounters another former top-10 player in Germany's Tommy Haas.

Hingis broke her opponent five times and won 81 percent (21-of-26) of points on her first serve as she improved to 34-3 lifetime at the Australian Open.

After failing to go an entire year without a Grand Slam singles title for the first time since 1996, Hingis is trying to start 2001 with her first major since winning here in 1999. The 20-year-old from Switzerland was denied a fourth straight title in Melbourne with a loss to Lindsay Davenport in last year's final.

Hingis is 9-0 this season after helping Switzerland win the Hopman Cup in Perth and capturing the adidas International last week in Sydney.

Williams committed 37 unforced errors, but hit 30 winners, vastly improving from her first-round total of nine over three sets.

"In general, I think I played a lot better," Williams said. "In my last match, I had nine winners. In this match I picked it up to 30. I was impatient a lot of times because (Shaughnessy) was a very speedy player and a lot of times I feel like I wanted to hit winners but at the wrong times."

Williams has not lost a Grand Slam match since falling to Arantxa Sanchez-Vicario in the quarterfinals of the French Open.

Venus' younger sister, Serena, is in action later Thursday as she takes on Russia's Nadejda Petrova. Seeded sixth, Serena Williams dispatched Janet Lee of Taipei in just over an hour in the first round. The Williams sisters are in the top half of the draw, along with Hingis, and could meet in the semifinals.

Among other seeded women, No. 7 Mary Pierce of France, the 1994 winner and reigning French Open champion, rolled into the third round with a 6-2, 6-2 victory over Argentina's Mariana Diaz-Oliva.

On the other hand, ninth seed Elena Dementieva of Russia, a semifinalist at last year's U.S. Open and the Olympic silver medalist, struggled in her second-round encounter with Andrea Glass of Germany. Dementieva saved a match point at 4-5 in the second set and rallied for a 2-6, 7-6 (8-6), 6-3 victory.

Also, two-time semifinalist Amanda Coetzer of South Africa, the 10th seed, dumped Silvija Talaja of Croatia, 6-1, 6-3, and 1999 runner-up Amelie Mauresmo of France, the 13th seed, downed Australian Nicole Pratt, 6-0, 7-5.

No. 16 Amy Frazier became the third women's seed to get knocked out as Rita Grande of Italy upended the American, 6-4, 6-1. Grande improved to 4-0 lifetime against Frazier and reached the third round in Melbourne for the third time in her career.

For the men, No. 11 Franco Squillari was the second seeded player to get eliminated as Canadian Daniel Nestor took out the Argentine, 3-6, 6-2, 6-4, 7-5.

French seeds Arnaud Clement and Sebastien Grosjean were straight-sets winners. Clement, the 15th seed, crushed Alberto Martin of Spain, 6-2, 6-1, 6-1. Grosjean, seeded 16th, dispatched Jan Siemerink of the Netherlands, 6-3, 6-0, 6-4.

In addition, fourth seed Magnus Norman of Sweden plays crafty Fabrice Santoro of France. Norman, a semifinlist here last year, recovered from a slow start to defeat Stephane Huet of France in four sets in the first round.

Also, 10th seed Wayne Ferreira of South Africa encounters Julien Boutter of France.

In a match of note involving unseeded players, 1997 finalist Carlos Moya of Spain, a former world No. 1 and French Open champion, disposed of Switzerland's Marc Rosset, 6-2, 6-1, 6-3.

On Wednesday, second seed Marat Safin, two-time champion Pete Sampras and defending champion Andre Agassi advanced to the third round.

Among the women to reach the third round were defending champion Lindsay Davenport and four-time champion Monica Seles. Fifth seed Conchita Martinez of Spain was upended by Switzerland's Emmanuelle Gagliardi.