Sampras, the third seed and two-time champion, snapped a rare three-match losing streak as he dispatched Germany's David Prinosil, 6-4, 6-4, to advance to the second round.

Hingis and Davenport, the top two seeds on the women's side, maintained their mastery over their respective opponents to reach the quarterfinals.

Hingis continued her march toward a third straight singles title as she got past No. 16 Barbara Schett, 6-3, 7-6 (7-4) and improved to 11-0 lifetime against the Austrian.

Davenport, bidding to become the first three-time champion at this event, improved to 10-0 lifetime against fellow American Lisa Raymond by defeating the 20th seed, 6-4, 6-2.

Third seed Venus Williams of the United States also cruised into the quarterfinals by downing lucky loser Rachel McQuillan of Australia, 6-4, 6-2.

Sampras was back to his old self in snapping his skid. He fired 17 aces and never lost his serve in winning his first match since reaching the fourth round at the Australian Open.

"I feel like I've been struggling a little bit over the last couple of weeks," he said. "Today, I felt like I got my game going and I was serving well. Hopefully, as the week goes on, I get some confidence and get some more matches under my belt."

Sampras improved to 23-10 lifetime at this event, which he won in 1994 and 1995.

Eighth seed Alex Corretja of Spain struggled in opening defense of his title. He rallied for a 3-6, 7-6 (7-2), 7-6 (7-4) win over Gaston Gaudio of Argentina to snap a two-match losing streak.

Australian Open champion Andre Agassi battles Hicham Arazi on Monday night, hoping to avenge a loss to the Moroccan here last year. Seeded fourth and a two-time runner-up, Agassi fell to Arazi in three sets last year to even the lifetime series at 1-1.

In other men's action, No. 12 Juan Carlos Ferrero of Spain, a winner two weeks ago at Dubai, faces Nicolas Massu of Chile. Also, Australian Open finalist Arnaud Clement of France, seeded 13th, crushed Australia's Andrew Ilie, 6-0, 6-3

Former world No. 1 Carlos Moya of Spain downed three-time champion Michael Chang of the United States, 6-4, 6-4, in an unseeded matchup of note.

A winner of seven career Tennis Masters Series titles, Chang fell to 26-9 lifetime at this event and saw his season record drop to 1-4.

Moya, a finalist in 1999, improved to 3-0 lifetime against Chang.

Hingis seemed in control against Schett. She was up a set and leading 4-2 in the second before Schett won three straight games and forced a set point on Hingis' serve at 4-5. But the world No. 1 came back to force a tiebreaker and eventually prevailed to extend her winning streak to 10 matches.

"When I needed it, I really made the points, and she would miss," Hingis said. "Then she just stopped missing, and I had to step it up a little bit. That's what I did."

Hingis, the 1998 champion, has won 28 of her first 30 matches in 2001. She captured the Qatar Open and Dubai Open in the Middle East last month for a WTA Tour-leading three titles this season.

In January, Hingis defeated Davenport to win the title at Sydney and lost to Jennifer Capriati in the Australian Open final before falling to Davenport in the final at Tokyo. The 20-year-old from Switzerland has reached the final in each of the five events she has played in 2001.

Davenport fired 11 aces and never faced a break in improving to 18-2 this season.

Two weeks ago, she won the State Farm Classic at Scottsdale, Arizona for her 32nd career title and second this year. The victory moved her within 1,250 points of Hingis for the top spot in the WTA Tour rankings. Davenport could move even closer by successfully defending her title.

Last year, she defeated Hingis in a three-set final and also took the title in 1997.

Seventh seed Serena Williams, Venus' younger sister, battles No. 12 Magdalena Maleeva of Bulgaria on Monday night, with the winner to face Davenport in the quarterfinals.

Serena Williams, the 1999 champion, is playing her first tournament since losing to Hingis in the Australian Open quarterfinals. She withdrew from events in Paris and Scottsdale due to exhaustion and the flu.

In other seeded women's action, Silvia Farina Elia of Italy eliminated No. 11 Anke Huber of Germany, 6-3, 4-6, 6-4.

On Monday night, eighth-seeded Elena Dementieva of Russia, a semifinalist last year, takes on countrywoman and qualifier Lina Krasnoroutskaya, and No. 14 Kim Clijsters of Belgium faces Ai Sugiyama of Japan.

This $4.95 million event offers a $330,000 first prize for the women's champion and $400,000 for the men's winner.