Serena Williams had a wobbly start at the Australian Open — for one game.

After briefly falling behind, Williams swept 10 consecutive games and beat Laura Siegemund 6-1, 6-1 on the first day of the tournament Monday.

The victory marked the start of Williams' latest bid for a record-tying 24th major title, and as she left the court, she flexed her biceps.

"This was a good start — vintage 'Rena," she said. "It's definitely good. I'm pretty good at pacing myself at a Grand Slam.” Williams wore a colorful one-legged catsuit, and her game looked flashy, too. She lost only nine points on her serve and hit 16 winners.

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.

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.

In early men's play, No. 14-seeded Milos Raonic defeated 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.

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 Australian Margaret Court's record of 24 major titles. Williams' most recent Grand Slam championship came at Melbourne in 2017.

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 Osaka breezed through the first set in 21 minutes and barely slowed after that. She finished with more winners than errors and lost only five points on her first serve.

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 on a cool day.

"I'm just really happy to see people in the stands," Osaka said.