Belinda Bencic of Switzerland on Monday became the fifth of the top 10 women's seeds to lose early at the BNP Paribas Open, echoing the fluctuation in the world rankings after No. 1 Serena Williams.
Bencic, ranked No. 8 and seeded seventh here, was victimized by her erratic serve and the forehand slices of world No. 97 Magdalena Rybarikova of Slovakia, who prevailed, 6-4, 3-6, 6-3, at Stadium 2 to advance to the round of 16.
Bencic's departure left ninth-seeded Roberta Vinci of Italy — a 6-1, 6-3 winner over No. 17 Elina Svitolina of Ukraine — as the highest remaining seed in the bottom half of the draw.
So far, No. 2 Angelique Kerber, No. 4 Garbine Muguruza, No. 6 Carla Suarez Navarro (injury) and No. 10 Venus Williams have exited, as have No. 11 Lucie Safarova, No. 14 Ana Ivanovic (beaten Monday by No. 18 Karolina Pliskova, 6-2, 6-0), No. 15 Sara Errani, No. 16 Svetlana Kuznetsova and No. 20 Caroline Wozniacki.
"I cannot explain for everyone but for me, OK, I am top 10 now and for sure they expect me to win every week and play very consistent results. It's just not the way it is," said Bencic, who turned 19 last week. "Everyone has a tough week and I cannot go every week and play my best tennis."
Tennis Hall of Famer Chris Evert, an ESPN commentator, said the upsets here reflect the unpredictability among the top women.
"After Serena, from 2 to 20, it's like musical chairs, anything can happen," Evert said during a conference call with reporters. "I think what really surprises me is the fact that still nobody has stepped up to the plate and challenged and is a consistent No. 2 player. . . . There isn't one other player out there that is mentally really fearless and strong enough to believe that they can challenge Serena."
In women's matches that went according to form, No. 12 Timea Bacsinszky of Switzerland slowed Eugenie Bouchard's effort to return from a slump and a concussion by defeating her, 6-2, 5-7, 6-2, and No. 26 Samantha Stosur needed three sets to get past Christina McHale, 6-4, 2-6, 6-4. . . . No. 13 Victoria Azarenka of Belarus — bundled up against the night chill — defeated wild-card entrant Shuai Zhang, 6-4, 6-3.
On the men's side, wrist problems caused Australia's Bernard Tomic to retire from his third-round match, giving No. 12 Milos Raonic of Canada a 6-3, 3-0 victory. No. 6 Tomas Berdych of the Czech Republic got past Croatian teenager Borna Coric, 6-1, 7-6, and No. 10 Marin Cilic of Croatia defeated Leonardo Mayer of Argentina, 6-4, 6-3. No. 13 Gael Monfils of France advanced with a 6-1, 6-3 victory over Albert Ramos-Vinolas of Spain and will face Federico Delbonis of Argentina, who upset No. 2 Andy Murray earlier in the day, and No. 18 Richard Gasquet of France defeated Alexandr Dolgopolov of Ukraine, 2-6, 6-2, 6-1. In the final match of the night, No. 3 seed Stan Wawrinka of Switzerland defeated Andrey Kuznetsov of Russia, 6-4, 7-6.