ROME -- The Williams sisters breezed into the Italian Open quarterfinals with impressive victories Thursday.
Venus Williams, the third seed, needed just 57 minutes to eliminate Anna Kournikova 6-2, 6-2, while No. 6 Serena Williams breezed by No. 13 Irina Spirlea of Romania 6-2, 6-3.
Serena's victory set up a clash with No. 1 Martina Hingis. The defending champion advanced by routing unseeded American Corina Morariu 6-1, 6-4 at night.
Both Williams siblings base their success on overpowering their foes with fierce strokes from both sides.
But they showed variety on the Foro Italico's red clay Thursday, disguising an occasional drop shot from the baseline or picking just the right moment for a slick volley.
"I would love to have a different game years from now," said Venus, at 18 a year older than Serena. "People get better, so if you don't improve your game, you get left behind. You just have to keep learning the game more."
Serena Williams has reached the final at each of the last three tournaments she's played, winning two, while her sister and Hingis each has won three titles.
"I think I have a better thought process as a player," Venus Williams said. "Last year, I was just developing, and hitting hard. Today, I'm able to think well, no matter who I am playing."
The sisters' showings so far on clay -- admittedly not their favorite surface, since it dulls their power -- indicates they should contend at the French Open, which starts May 24.
The defending champion in the French Open, Arantxa Sanchez-Vicario, was eliminated from the Italian Open on Thursday with a dispirited 6-4, 6-1 loss to unseeded Austrian Sylvia Plischke. Sanchez-Vicario, seeded second, said she was hampered by a wrist injury nagging her since November.
Also, 1997 Italian Open champion and No. 4 seed Mary Pierce ousted No. 15 Conchita Martinez 4-6, 6-0, 7-6 (7-2). Martinez, a four-time titlist in Rome, blew a match point while serving in the 12th game of the decisive set.
No. 10 Amelie Mauresmo, the surprise finalist at the Australian Open, and No. 11 Dominique Van Roost also reached the round of eight. Mauresmo came back from a set down to beat No. 5 Patty Schnyder 5-7, 6-2, 6-4, while Van Roost knocked out No. 7 Nathalie Tauziat 6-4, 7-6 (7-2).