Venus, making her 20th appearance at Melbourne Park 24 years after her first, was thrilled to beat 35-year Belgian Kirsten Flipkens 7-5 6-2 in a battle of two of the tour's old-timers.

"Oh, my gosh, great. Winning is always fun. Never easy," the 40-year-old said.

"She's definitely tricky. We've had some great battles in the past, as well."

Williams, who won the last of her seven major titles at Wimbledon in 2008, insisted age was but a number when asked if being 40 was on her mind when she took the court.

"Would it be front of mind for you if you were playing a professional tennis match," the American said.

"I like my job. This is Job A. I have a good team."

Her team includes younger sister Serena, who herself turns 40 this year. The siblings boast an incredible 30 grand slam singles titles and eight Olympic gold medals between them.

Little wonder Williams says Serena remains the best hitting partner in the business.

"You definitely don't want to miss because it's your sister, so you want to give her a good practice," she said.

"Also her intensity level just raises your level. Yeah, we definitely had some good practices. I think it definitely helped both of us."

So it looked as Serena needed less than an hour to follow the oldest player in the women's draw into the second round with a 6-1 6-1 dispatch of German Laura Siegemund.

The seven-times champion already looks the biggest threat in the bottom half of the draw to title favourite and third seed Naomi Osaka.

Osaka dropped only one game more than Serena in swatting aside three-time quarter-finalist Anastasia Pavlyuchenkova 6-1 6-2 in her opener.

Canadian youngster Bianca Andreescu could yet prove a factor after making a successful return from more than 15 months out with injury.

The world No.9 and former US Open champion beat Mihaela Buzarnescu 6-2 4-6 6-3 victory in her first outing since the 2019 WTA Finals.

Teenage sensation Iga Swiatek wasted little time making her mark at Melbourne Park, cruising into the second round with a straight-sets win over Arantxa Rus.

The 19-year-old French Open champion extended her grand slam winning streak to eight matches in seeing off Rus 6-1 6-3.

But three-times grand slam champion Angelique Kerber was unable to overcome two weeks of hard quarantine, the German losing 6-0 6-4 to American Bernarda Pera.

One of the 72 players forced into total hotel lockdown after arriving in Melbourne last month, Kerber won the title in Melbourne five years ago.

But her 2021 campaign lasted barely an hour.

Australian Associated Press