MELBOURNE, Australia (AP) — Serena Williams arrived ready to race at the Australian Open.

Wearing a colorful one-legged catsuit that she said was inspired by former Olympic sprint champion Florence Griffith Joyner, Williams shook off a wobbly start — opening with a double-fault and dropping her first service game — to sweep 10 consecutive games and beat Laura Siegemund 6-1, 6-1 on the first day of the tournament.

The victory marked the start of Williams’ latest bid for a record-tying 24th major title. As she left the court she flexed her biceps, and later she donned a T-shirt that read “Unstoppable Queen.”

She described her opening match as “vintage ’Rena,” and showed no signs of the right shoulder issue that led her to pull out of the semifinals of a tuneup tournament last week.

Griffith Joyner was a sprinting and fashion icon in the 1980s, setting the world records for the women’s 100- and 200-meter sprints. She died in 1998, the same year Serena Williams contested her first Australian Open.

“Yeah, I was inspired by Flo Jo, who was a wonderful track athlete, amazing athlete when I was growing up,” Williams said. “Well, watching her fashion, just always changing, her outfits were always amazing.

“This year we thought of what can we do to keep elevating the Serena Williams on the court.”

It’s off to a flyer.

She wasn’t the first Williams to reach the second round, however. Her sister, Venus, won a Grand Slam match for the first time since 2019.

Playing in her 21st Australian Open, the elder Williams beat Kirsten Flipkens 7-5, 6-2. At 40, Venus is the oldest woman in this year’s draw and just the sixth player in her 40s to compete at the Australian Open.

“I like my job,” she said. “No matter what happens to you in life, you always hold your head up high and give 100 million percent. And that’s what I do every single day, and that’s something I can be proud of.”

Three-time Grand Slam champion Naomi Osaka, who won the title in Melbourne two years ago, played the opening match in Rod Laver Arena and beat Anastasia Pavlyuchenkova 6-1, 6-2.

The first tournament of this year’s Grand Slam season began after a three-week delay because of the coronavirus pandemic.

“Physically I feel like everyone, their bodies are shocked, coming in and playing so suddenly after such a long break,” Osaka said. “I think we’re all getting used to it and everyone is just happy to be here.”

That includes the Williams sisters.

“Listen, this is amazing,” Serena said. “Last year was very scary for the world. To be able to do what I love and be able to come out and compete . . . it makes me appreciate the moment even more.”

Canadian Rebecca Marino, a former top-40 player competing in a Grand Slam event for the first time in eight years, beat wild-card entry Kimberly Birrell 6-0, 7-6 (9). Marino was sidelined by depression and a serious foot injury.

No. 23 Angelique Kerber, a three-time major champion and 2016 Australian Open winner, lost to American Bernarda Pera 6-0, 6-4.

U.S. Open champion Dominic Thiem was a break down and saved set points before beating veteran Mikhail Kukushkin 7-6 (2), 6-2, 6-3 in his first match at the tournament since losing last year’s final to top-ranked Novak Djokovic.

No. 14 Milos Raonic was the first man to finish the first round, beating Federico Coria 6-3, 6-3, 6-2. American Reilly Opelka hit 18 aces and beat Lu Yen-hsun 6-3, 7-6 (2), 6-3.

No. 10-seeded Gael Monfils lost a marathon against Emil Ruusuvuori 3-6, 6-4, 7-5, 3-6, 6-3.

Serena Williams overpowered Siegemund, moved well and saved one of her best shots for the final game, racing forward to flip an off-balance backhand off her shoestrings for a cross-court winner.

For the past four years, Williams has been trying to equal Margaret Court’s record of 24 major titles. Williams’ most recent Grand Slam championship came at Melbourne in 2017.

“I’ve had a ton of pressure, and now I don’t feel it anymore,” she told ESPN after her first-round win. “It’s like a huge relief. I think I was just looking at it all the wrong way in the past, and I feel totally different about it now.”

Osaka drew a potential tough opening opponent in Pavlyuchenkova, a Russian ranked 39th who reached the quarterfinals in Melbourne three of the past four years. But she breezed through the first set in 21 minutes and barely slowed after that.

Up to 30,000 fans — about 50% of capacity — will be allowed on the tournament site, but seats were mostly empty for the early matches.

“I’m just really happy to see people in the stands,” Osaka said.

___

AP Sports Writer Steven Wine contributed from Miami.

___

More AP tennis: https://apnews.com/hub/tennis and https://twitter.com/AP_Sports