The day after No.1 Ashleigh Barty left the singles tournament without a win, the status quo regained its grip Monday at the Olympic Games in Tokyo.  

In the seven early matches at Ariake Tennis Park, the higher-ranked players all prevailed in straight sets.

No.2 Naomi Osaka, who became the favorite after Sara Sorribes Tormo sent Barty home, looked fluid and forceful in a 6-3, 6-2 victory over Viktorija Golubic.

In advancing to the third round – and a match against Marketa Vondrousova – Osaka hasn’t dropped a set, and her serve and backhand have been invincible.

After missing 56 consecutive days without a match, there were questions concerning Osaka’s ability to manage the pressure of winning gold in her home country of Japan.

So far, so good.

“Honestly, it’s a bit interesting,” she said of playing for the host nation. “The [Japanese] flag is always next to my name, but the scale here is much bigger.

“It’s something I’ve been waiting for since Rio.”

Upset alert: Swiatek, Sabalenka and Kvitova fall Monday in Tokyo

Osaka played a terrific first set, winning 24 of her 26 service points and converting her first set point with her eighth backhand winner of the frame.

She won 37 of 45 service points (82 percent) and faced only one break point.

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“More than anything else, I’m just focused on playing tennis,” Osaka told reporters after her first-round match, a 6-1, 6-4 win over China’s Zheng Saisai. “The Olympics has been a dream of mine since I was a kid, so I feel like the break that I took was very needed.

“I feel definitely a little bit refreshed, and I’m happy again.”

Similarly, No.7 Garbiñe Muguruza had no issues in a 6-3, 6-0 victory against Wang Qiang in only 61 minutes. This was Muguruza’s 29th match-win of the season.

Muguruza broke Wang, who had won their previous two head-to-head matches, five times.

No. 8 Barbora Krejcikova was nearly as dominant.

She’s now won 22 of her past 23 matches after handling 18-year-old Canadian Leylah Fernandez 6-2, 6-4.

The French Open champion, hitting characteristically smooth groundstrokes, needed 75 minutes to complete the match. Krejcikova next plays No.9 Belinda Bencic.

Photo by Kopatsch/Sato/Sidorjak/ITF

No.13 Anastasia Pavlyuchenkova defeated Anna-Lena Friedsam 6-1, 6-1 – and has lost only three games in two matches. On the opening day of the Olympics, Pavlyuchenkova took down Sara Errani 6-0, 6-1.

On Monday, Pavlyuchenkova ended the match in 56 minutes and won a remarkable 53 of 73 points. She’ll meet the winner of Sara Sorribes Tormo and Fiona Ferro.

No.14 Maria Sakkari had no trouble handling Nina Stojanovic 6-1, 6-2.

Sakkari, the 26-year-old from Greece, dominated the service game, stroking five aces and breaking Stojanovic four times. Sakkari next takes on No.4 Elina Svitolina in what should be a highly anticipated third-round match.

No.15 Elena Rybakina defeated Rebecca Peterson 6-2, 6-3. This was the 22-year-old from Kazakhstan’s 21st match-win of the year.

The highlight of Rybakina’s season so far was a straights-sets win over Serena Williams to advance to the quarterfinals of the French Open.

In the only unseeded early match, Italy’s Camila Giorgi bested Elena Vesnina 6-3, 6-1. This followed her first-round upset of No.11 seed Jennifer Brady, 6-3, 6-2.

Giorgi had lost two of three matches to Vesnina, but they hadn’t played in four years. The Italian hit 20 winners and broke Vesnina five times. She’ll see No.5 seed Karolina Pliskova in the third round.