The quarterfinals of the women's singles tennis tournament came into focus Tuesday at the 2021 Summer Olympics in Tokyo.

Naomi Osaka's quest for gold came to an end against Marketa Vondrousova in the round of 16. Fifth-seeded Karolina Pliskova was also upset by Camila Giorgi, while Elina Svitolina, Garbine Muguruza and Belinda Bencic were among the day's notable winners.

Of course, all eyes were on Osaka in her home country.

Women's Singles Third-Round Results

Marketa Vondrousova def. No. 2 Naomi Osaka; 6-1, 6-4

No. 13 Anastasia Pavlyuchenkova def. Sara Sorribes Tormo; 6-1, 6-3

No. 8 Belinda Bencic def. No. 9 Barbora Krejcikova; 1-6, 6-2, 6-3

No. 15 Elena Rybakina def. Donna Vekic; 7-6, 6-4

No. 7 Garbine Muguruza def. Alison Van Uytvanck; 6-4, 6-1

Camila Giorgi def. No. 5 Karolina Pliskova; 6-4, 6-2

No. 4 Elina Svitolina def. No. 14 Maria Sakkari; 5-7, 6-3, 6-4

Paula Badosa def. Nadia Podoroska; 6-2, 6-3

Recap

The warning signs came early for Osaka in the first set as she dropped her first two service games and fell behind 0-4. The four-time Grand Slam champion wasn't her usual self as she committed 14 unforced errors in the opening set.

Vondrousova did her part to roll through the opening frame. The 22-year-old Czech overpowered her opponent at times and didn't hesitate to utilize her heavy left-handed forehand.

With an opportunity to reset, things were looking up for Osaka to get the second set underway. She broke Vondrousova's serve in the first game and jumped ahead 2-0. However, the next two games confirmed the 23-year-old remained in a tough battle as Vondrousova broke back to tie the set at 2-2.

The two exchanged serve until Osaka was attempting to stay alive at 4-5. She managed to stave off a pair of match points after falling behind 15-40. Vondrousova kept ramping up the pressure, though, and the third match point was the charm.

A cross-court backhand from Osaka sailed wide to seal the upset. She finished with 32 unforced errors, more than triple the number of her opponent (10). Vondrousova, meanwhile, registered four aces and 18 groundstroke winners.

Between taking down Kiki Bertens in the first round and soundly defeating Osaka, she could be a tough out in the quarterfinals.

The day's other spotlight matchup was a top-10 clash between Bencic and Krejcikova, which went the three-set distance.

Krejcikova looked downright dominant in the first set, tallying six aces and five winners to grab the early advantage. Bencic stormed back over the final two sets, however, and took full advantage of 13 unforced errors by her Czech Republic counterpart in the deciding set.

It wasn't the most efficient match for Bencic, who racked up 36 unforced errors, but her 15 winners and five breaks of serve were enough to advance as Krejcikova's form dropped considerably after the opening set.

The women's quarterfinals will take place Wednesday in Tokyo. With Osaka eliminated, it's a wide-open battle for the Olympic gold medal.