So there was a turn-back-the-clock feel to day one at the 2013 US Open, when both sisters were about as good as can be, dropping a combined four games in Arthur Ashe Stadium. Venus, now ranked 60th, beat 12thseeded Kirsten Flipkens 6-1, 6-2 on Monday afternoon, and then Serena reduced 2010 French Open champion Francesca Schiavone to seeking comfort from a ball boy's hug during a 6-0, 6-1 runaway under the lights at night.

Asked which meant more on this day, her own victory or her sister's, Serena replied: "They're equal. I definitely was happy to see Venus win. I really was happy for her. I know she's been working hard. I know she had a tough opponent. For her to come through was just awesome. Obviously, I want to do well, too."

For years and years, a first-round victory by Venus at a major tournament would hardly merit a mention. She has won seven grand slam titles and was the runner-up another seven times [six against Serena].

And yet nowadays, at age 33, two years removed from being diagnosed with an auto-immune disease that saps energy and hampered much of this season by a bad lower back, Venus entered this US Open having won a total of three matches over the past five major tournaments. Plus, in Flipkens, she was facing a semi-finalist at Wimbledon last month who beat Venus on a hard court this month.

Looking very much like the player she used to be, Venus smacked serves at up to 190km/h, returned superbly and covered the court well enough to hit a handful of swinging volley winners.

"If Venus is there - if she's fit, if she's focused - she's a top-10 player," Flipkens said. "Everybody who knows a little bit of the game of tennis can see that. Today, she was like a top-10 player."

On a day that began with a retirement announcement by James Blake - a former top-five player who also is 33 - Venus showed she's still capable of big shots at big moments.

"I stay positive because I know I can play great tennis. Sometimes you just have to go through more than what you want to go through," the American said. "Sometimes you have to have losses."

She was No1 in 2002, but hasn't cracked the top 10 since she was No9 in March 2011. She hasn't been past the third round at a grand slam tournament since a fourth-round exit at Wimbledon later that year. Indeed, Venus lost in the first round in two of her previous four appearances at majors.

Her match was the day's second in the main stadium, and there were thousands of empty blue seats in the 23,000-capacity arena.

The place was full for the night session, however, when the No1-ranked and No1-seeded Serena won the first eight games, prompting Schiavone, in a brief moment of levity, to walk behind a baseline and envelop a ball boy in a full embrace.

"I don't need a hug in that moment," Schiavone joked afterwards. "I need a game."

It was that kind of evening for Schiavone, a demonstrative player who is certainly no pushover: In addition to her triumph at Roland Garros three years ago, she was the runner-up there a year later, and twice was a US Open quarter-finalist. Ranked as high as No4, she is 54th this week.

"I knew playing a former grand slam champion in the first round was a really, really tough draw," Serena said, "so I tried to be super serious."

When Schiavone finally got on the board more than 50 minutes into her match against Serena, hitting a volley winner to hold serve and win her first game, she swung her right fist in a celebratory punch and shouted.

"It was very, very nice to win a game," Schiavone said. "For the first time in my life, I felt joy from winning a single game."

At Serena's news conference, she was asked by an Italian reporter: "Did you really want to win 6-0, 6-0 against the poor Schiavone?"

That drew a chuckle from Serena, who responded: "No, it wasn't that. I was just out there, trying to be focused."

She is seeking her fifth US Open championship and 17th grand slam title overall. She improved to 61-4 with a tourleading eight titles this season.

It's been tougher going for Venus, who is only 12-7 and last won a tournament in October last year.

If Venus and Serena both win three more matches in New York, they would set up an all-Williams quarter-final.

That seems a long way away at the moment. So does the stretch when they played each other in four consecutive grand slam finals in 2002-03.

"I realise that I haven't had a lot of chances to play this year or a lot of chances to play healthy this year, have had injuries and what have you, so I'm just going to have to keep working my way into it, maybe more than some of the other players," Venus said. "But I know I can do that."